Multiply the following polynomials;
(1)
[tex]\begin{gathered} (3x-8)\times(4x+7) \\ =(3x\times4x)+(3x\times7)-(8\times4x)-(8\times7) \\ =12x^2+21x-32x-56 \\ =12x^2-11x-56 \end{gathered}[/tex](2)
[tex]\begin{gathered} (4x+7)^2 \\ =(4x+7)(4x+7) \\ =(16x^2+28x+28x+49) \\ =16x^2+56x+49 \end{gathered}[/tex](3)
[tex]\begin{gathered} (3x-8)(3x+8) \\ =9x^2+24x-24x-64 \\ =9x^2+0-64 \\ 9x^2-64 \end{gathered}[/tex]