Question

Me ajudem a responder
(-x+4) (x+5)

Answer 1

(-x+4) (x+5)

-x²-5x+4x+20

-x²-x+20=0

∆=b²-4•a•c

∆=(-1)²-4•(-1)•20

∆=1+80

∆=81

-b±√∆/2•a

-(-1)±√81/2•-1

1±9/-2

X¹=1+9/-2

10/-2

-5

X²=1-9/-2

-8/-2

4

Prontinho! ;)