Question

Ache as raizes da função f(x)= (x+3).(x-5)

Answer 1

f(x)= (x+3).(x-5)

x²-5x+3x-15

x²-2x-15

Δ=(-2)²-4*1*(-15)

Δ=4+60

Δ=64

x=$\frac{-(-2)+\sqrt{64}}{2*1}$

x=$\frac{2+8}{2}$

x=$\frac{10}{2}$

x=5

x=$\frac{-(-2)-\sqrt{64}}{2*1}$

x=$\frac{2-8}{2}$

x=$\frac{-6}{2}$

x=-3