1. As we need the zeros to be on 4 and -7, the factored expression must be:
[tex](x-4)(x+7)[/tex]
And by multiplying
[tex]x^2+7x-4x-28[/tex][tex]x^2+3x-28[/tex]
2. By using the quadratic formula we get:
[tex]\frac{-8\pm\sqrt[]{8^2-4\cdot4\cdot7}}{2\cdot4}[/tex][tex]\frac{-8\pm\sqrt[]{64^{}-112}}{8}[/tex][tex]\frac{-8\pm\sqrt[]{-48}}{8}[/tex][tex]\frac{-8}{8}\pm\frac{\sqrt[]{-48}}{8}[/tex][tex]-1\pm\frac{\sqrt[]{16\cdot3\cdot-1}}{8}[/tex][tex]-1\pm\frac{\sqrt[]{16}\cdot\sqrt[]{3}\cdot\sqrt[]{-1}}{8}[/tex][tex]-1\pm\frac{4\cdot\sqrt[]{3}\cdot i}{8}[/tex][tex]-1\pm\frac{\cdot\sqrt[]{3}\cdot i}{2}[/tex][tex]-1\pm\frac{i\cdot\sqrt[]{3}}{2}[/tex]
