Question

$2 {x }^{2} - 7x - 15 = 0$
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Answer 1

Resposta: S={( 5 , -3/2 )}

2x²-7x-15=0

a=2 b=-7 c=-15

∆=(-7)²-4.(2).(-15)

∆=49-8.(-15)

∆=49+120

∆=169

x'=[-(-7)+√169]/2.(2)

x'=[7+13]/4

x'=20/4

x'=5

x"=[-(-7)-√169]/2.(2)

x"=[7-13]/4

x"=-6/4 = (-6÷2)/(4÷2)=-3/2