Question

How do you find the roots, real and imaginary, of `y= -2x^2 + 5x + 72` using the quadratic formula?

Answer 1

`color(maroon)("Two roots are " x = (5 + sqrt(601)) / 4, (5 - sqrt(601)) / 4`

Explanation:

`"Quadratic Formula " x = (-b +- sqrt(b^2 - 4ac)) / (2a)`

`"Given " y = -2x^2 + 5x + 72`

`= -2, b = 5, c = 72`

`x = (-5 +- sqrt(25 + (4 * 2 * 72))) / (2 * -2)`

`x = (-5 +- sqrt(601)) / -4`

`color(maroon)(x = (5 +- sqrt(601)) / 4`