Answer:
[tex]x=\displaystyle\frac{3\pm\sqrt{569}}{4}[/tex]
Step-by-step explanation:
Hi there!
[tex]f(x) = -2x(x+7)+10x+70\\f(x) = -2x^2-7x+10x+70\\f(x) = -2x^2+3x+70[/tex]
We can solve this by using the quadratic formula, which states:
[tex]x=\displaystyle\frac{-b\pm\sqrt{b^2-4ac}}{2a}[/tex] where [tex]f(x)=ax^2+bx+c[/tex]
Plug in the values a, b and c:
[tex]x=\displaystyle\frac{-3\pm\sqrt{3^2-4(-2)(70)}}{2(-2)}\\\\x=\displaystyle\frac{-3\pm\sqrt{9+560}}{-4}\\\\x=\displaystyle\frac{-3\pm\sqrt{569}}{-4}\\\\x=\displaystyle\frac{3\pm\sqrt{569}}{4}[/tex]
I hope this helps!
