Question

Quais são as raizes da função f(x) = 2 x² - x - 10

Answer 1

vamos lá...

f(x)=2x²-x-10

2x²-x-10=0

a=2
b=-1
c=-10

Δ=b²-4ac
Δ=(-1)²-4(2)(-10)
Δ=1+80
Δ=81

$x= \frac{-b\pm \sqrt{\triangle} }{2a} =~~ \frac{-(-1)\pm \sqrt{81} }{4} =~~ \frac{1\pm9}{4} \\ \\ x'= \frac{1+9}{4} = \frac{10}{4} = \frac{5}{2} \\ \\ x"= \frac{1-9}{4} =- \frac{8}{4} =-2$