Question

dada afunção y=9x²-8x-1 determine os valores para os quais y=0

Answer 1

Resposta:

para y=0

9x² - 8x - 1=0

a=9

b=-8

c=-1

Δ=b²-4ac

Δ=(-8)²-4(9)(-1)

Δ=64+36

Δ=100

$x={-b\pm\sqrt{\Delta} \over2a}={-(-8)\pm\sqrt{100} \over2.(9)}={8\pm10\over18}\\ \\ x_1={8-10\over18}=-{2\over18}=-{1\over9}\\ \\ x_2={8+10\over18}={18\over18}=1\\ \\ S=\{-{1\over9},1\}$