Question

calule x²-5x=8 para x =2

Answer 1

x²-5x=8
x²-5x-8=0
A=1
B=(-5)
C=(-8)
∆=(-5)²-4.1.(-8)
∆=25-32=-7
x=-(-5)±√-7=5±√-7
———— ————
2.1 2

Portanto x'= 5 + raíz de -7/ 2 e x"= 5 - raíz de -7 /2