Question

Please help with this

Answer 1

C.
`c = (-7+-√(129) )/(8)`

Explanation:

Before we start, you can think of the variable "c," as x.

The quadratic formula/equation is:

`x = (-b+-√(b^2-4ac) )/(2a)`

The setup is:

`ax^2+bx+c=0`

`4c^2+7c-5=0`

Plug in the numbers accordingly to the letter associated, like so:

`x = (-7+-√(7^2-4(4)(-5)) )/(2(4))`

`x = (-7+-√(49+80) )/(8)`

`x = (-7+-√(129) )/(8)`