\documentclass{article}
\usepackage{amsmath}
\usepackage{multicol}
\usepackage{exsheets}
\usepackage{tasks}

\SetupExSheets{solution/print=true}

\begin{document}

\begin{examplebox}
    \subsection{Examples:}
    \begin{questions}
        \question[14] Factorise:
        \begin{parts}\begin{multicols}{2}
            \part \(25-y^{2}\)
            \begin{solutionordottedlines}[1in]
                \(25-y^{2}=5^{2}-y^{2}\)

                \[
                =(5+y)(5-y)
                \]
            \end{solutionordottedlines}
            \part \(4 x^{2}-9\)
            \begin{solutionordottedlines}[1in]
                \(4 x^{2}-9=(2 x)^{2}-3^{2}\)

                \[
                =(2 x+3)(2 x-3)
                \]
            \end{solutionordottedlines}
            \part \(3 a^{2}-27\)
            \begin{solutionordottedlines}[1in]
                \(3 a^{2}-27=3(a^{2}-9)\)
                \(=3(a+3)(a-3)\)
            \end{solutionordottedlines}
            \part \(-16+9 x^{2}\)
            \begin{solutionordottedlines}[1in]
                \(-16+9 x^{2}=9 x^{2}-16\)
                \(=(3 x)^{2}-4^{2}\)
                \(=(3 x-4)(3 x+4)\)
            \end{solutionordottedlines}
        \question[5] Use the factorisation of the difference of two squares to evaluate the following. One has been done for you.
        \[
        \begin{aligned}
        17^{2}-3^{2} & =(17+3)(17-3) \\
        & =20 \times 14 \\
        & =280
        \end{aligned}
        \]
        \begin{parts}\begin{multicols}{2}
            \part \(23^{2}-7^{2}\)
            \begin{solutionordottedlines}[1in]
                \(23^{2}-7^{2}=(23+7)(23-7)\)
                \(=30 \times 16\)
                \(=480\)
            \end{solutionordottedlines}
            \part \(94^{2}-6^{2}\)
            \begin{solutionordottedlines}[1in]
                \(94^{2}-6^{2}=(94+6)(94-6)\)
                \(=100 \times 88\)
                \(=8800\)
            \end{solutionordottedlines}
            \part \(11.3^{2}-8.7^{2}\)
            \begin{solutionordottedlines}[1in]
                \(11.3^{2}-8.7^{2}=(11.3+8.7)(11.3-8.7)\)
                \(=20 \times 2.6\)
                \(=52\)
            \end{solutionordottedlines}
            \part \(4^{2}-3^{2}\)
            \begin{solutionordottedlines}[1in]
                \(4^{2}-3^{2}=(4+3)(4-3)\)
                \(=7 \times 1\)
                \(=7\)
            \end{solutionordottedlines}
        \end{multicols}\end{parts}
    \end{questions}

    Note: You can always check your factorisation is correct by expanding your result and checking to see if that is the expression you started with!
\end{examplebox}

\begin{exercisebox}
    \subsection{Exercises:}

    \begin{questions}
        \question[16] Factorise:
        \begin{parts}\begin{multicols}{2}
            \part \(x^{2}-49\)
            \begin{solutionordottedlines}[1in]
                \(x^{2}-49=(x+7)(x-7)\)
            \end{solutionordottedlines}
            \part \((3 x)^{2}-16\)
            \begin{solutionordottedlines}[1in]
                \((3 x)^{2}-16=(3x+4)(3x-4)\)
            \end{solutionordottedlines}
            \part \(16 y^{2}-49\)
            \begin{solutionordottedlines}[1in]
                \(16 y^{2}-49=(4y+7)(4y-7)\)
            \end{solutionordottedlines}
            \part \(9-16 y^{2}\)
            \begin{solutionordottedlines}[1in]
                \(9-16 y^{2}=(3+4y)(3-4y)\)
            \end{solutionordottedlines}
            \part \(a^{2}-121\)
            \begin{solutionordottedlines}[1in]
                \(a^{2}-121=(a+11)(a-11)\)
            \end{solutionordottedlines}
            \part \((4 x)^{2}-1\)
            \begin{solutionordottedlines}[1in]
                \((4 x)^{2}-1=(4x+1)(4x-1)\)
            \end{solutionordottedlines}
            \part \(100 a^{2}-49 b^{2}\)
            \begin{solutionordottedlines}[1in]
                \(100 a^{2}-49 b^{2}=(10a+7b)(10a-7b)\)
            \end{solutionordottedlines}
            \part \(25 a^{2}-100 b^{2}\)
            \begin{solutionordottedlines}[1in]
                \(25 a^{2}-100 b^{2}=(5a+10b)(5a-10b)\)
            \end{solutionordottedlines}
            \part \(d^{2}-400\)
            \begin{solutionordottedlines}[1in]
                \(d^{2}-400=(d+20)(d-20)\)
            \end{solutionordottedlines}
            \part \(4 x^{2}-100\)
            \begin{solutionordottedlines}[1in]
                \(4 x^{2}-100=(2x+10)(2x-10)\)
            \end{solutionordottedlines}
            \part \(5 x^{2}-45\)
            \begin{solutionordottedlines}[1in]
                \(5 x^{2}-45=5(x^{2}-9)\)
                \(=5(x+3)(x-3)\)
            \end{solutionordottedlines}
            \part \(7 x^{2}-63\)
            \begin{solutionordottedlines}[1in]
                \(7 x^{2}-63=7(x^{2}-9)\)
                \(=7(x+3)(x-3)\)
            \end{solutionordottedlines}
            \part \(8 x^{2}-50\)
            \begin{solutionordottedlines}[1in]
                \(8 x^{2}-50=2(4x^{2}-25)\)
                \(=2(2x+5)(2x-5)\)
            \end{solutionordottedlines}
        \end{multicols}\end{parts}
        \begin{parts}\begin{multicols}{2}
            \setcounter{partno}{12}
            \part \(20-5 y^{2}\)
            \begin{solutionordottedlines}[1in]
                \(20-5 y^{2}=5(4-y^{2})\)
                \(=5(2+y)(2-y)\)
            \end{solutionordottedlines}
            \part \(27 a^{2}-12 b^{2}\)
            \begin{solutionordottedlines}[1in]
                \(27 a^{2}-12 b^{2}=3(9a^{2}-4b^{2})\)
                \(=3(3a+2b)(3a-2b)\)
            \end{solutionordottedlines}
            \part \(27 a^{2}-192 l^{2}\)
            \begin{solutionordottedlines}[1in]
                \(27 a^{2}-192 l^{2}=3(9a^{2}-64l^{2})\)
                \(=3(3a+8l)(3a-8l)\)
            \end{solutionordottedlines}
            \part \(-8 x^{2}+32 y^{2}\)
            \begin{solutionordottedlines}[1in]
                \(-8 x^{2}+32 y^{2}=32 y^{2}-8 x^{2}\)
                \(=8(4y^{2}-x^{2})\)
                \(=8(2y+x)(2y-x)\)
            \end{solutionordottedlines}
            \part \(-4+9 x^{2}\)
            \begin{solutionordottedlines}[1in]
                \(-4+9 x^{2}=9 x^{2}-4\)
                \(=(3x+2)(3x-2)\)
            \end{solutionordottedlines}
            \part \(-100 x^{2}+9\)
            \begin{solutionordottedlines}[1in]
                \(-100 x^{2}+9=9-100 x^{2}\)
                \(=(3+10x)(3-10x)\)
            \end{solutionordottedlines}
            \part \(-36 x^{2}+400\)
            \begin{solutionordottedlines}[1in]
                \(-36 x^{2}+400=400-36 x^{2}\)
                \(=(20+6x)(20-6x)\)
            \end{solutionordottedlines}
            \part \(23^{2}-3^{2}\)
            \begin{solutionordottedlines}[1in]
                \(23^{2}-3^{2}=(23+3)(23-3)\)
                \(=26 \times 20\)
                \(=520\)
            \end{solutionordottedlines}
            \part \(1.8^{2}-0.2^{2}\)
            \begin{solutionordottedlines}[1in]
                \(1.8^{2}-0.2^{2}=(1.8+0.2)(1.8-0.2)\)
                \(=2 \times 1.6\)
                \(=3.2\)
            \end{solutionordottedlines}
            \part \(92.6^{2}-7.4^{2}\)
            \begin{solutionordottedlines}[1in]
                \(92.6^{2}-7.4^{2}=(92.6+7.4)(92.6-7.4)\)
                \(=100 \times 85.2\)
                \(=8520\)
            \end{solutionordottedlines}
            \part  \(5^{2}-4^{2}\)
            \begin{solutionordottedlines}[1in]
                \(5^{2}-4^{2}=(5+4)(5-4)\)
                \(=9 \times 1\)
                \(=9\)
            \end{solutionordottedlines}
            \part  \(9^{2}-8^{2}\)
            \begin{solutionordottedlines}[1in]
                \(9^{2}-8^{2}=(9+8)(9-8)\)
                \(=17 \times 1\)
                \(=17\)
            \end{solutionordottedlines}
            \part \(6^{2}-5^{2}\)
            \begin{solutionordottedlines}[1in]
                \(6^{2}-5^{2}=(6+5)(6-5)\)
                \(=11 \times 1\)
                \(=11\)
            \end{solutionordottedlines}
            \part \(10^{2}-9^{2}\)
            \begin{solutionordottedlines}[1in]
                \(10^{2}-9^{2}=(10+9)(10-9)\)
                \(=19 \times 1\)
                \(=19\)
            \end{solutionordottedlines}
        \end{multicols}\end{parts}
    \end{questions}

\end{exercisebox}

\end{document}
