Question

x oa quadrado-10x+9=0

Answer 1

x²-10x+9=0
a=1
b=-10
c=9
Δ=(-10)²-4.1.9
Δ=100-36
Δ=64

$\frac{-(-10)+/- \sqrt{64} }{2.1} \\ \frac{10+/- 8}{2} \\ x'= \frac{10+8}{2} = \frac{18}{2} = 9 \\ x"= \frac{10-8}{2} = \frac{2}{2} = 1$
espero ter ajudado!