Respuesta :

altavistard
Please equate 2x^2 -8x -90 to zero:    2x^2 -8x -90=0

Next, reduce 2x^2 -8x -90=0 by div. all terms by 2:    x^2 -4x -45=0

Next, factor the poly:  (x-9)(x+5) = 0

Set each factor = to 0 and solve for x:

x-9=0 => x=9
x+5=0 => x= -5