Question

Find the zeros of the function: f(x)=-2x(x+7)+10x+70

Answer 1

`x=\displaystyle(3\pm√(569))/(4)`

Explanation:

Hi there!

`f(x) = -2x(x+7)+10x+70\\f(x) = -2x^2-7x+10x+70\\f(x) = -2x^2+3x+70`

We can solve this by using the quadratic formula, which states:

`x=\displaystyle(-b\pm√(b^2-4ac))/(2a)` where
`f(x)=ax^2+bx+c`

Plug in the values a, b and c:

`x=\displaystyle(-3\pm√(3^2-4(-2)(70)))/(2(-2))\\\\x=\displaystyle(-3\pm√(9+560))/(-4)\\\\x=\displaystyle(-3\pm√(569))/(-4)\\\\x=\displaystyle(3\pm√(569))/(4)`

I hope this helps!