Question

Determine o zero da função
f(x)= -x²+8x-15

Answer 1

a=1
b=8
c=--15
x= - (8) ± √ (8)² -4 . 1 . -15/2 . 1
x= -8 ± √ 64 -4.1.-15/2
x=-8 ± √ 4/2
x'=-8+2/2
x'=-7
x'=-8-2/2
x'=-9