Question

Um valor de x que satisfaz a igualdade x²-14=5x é: * 10 pontos A) 2 B) 7 C) 5 D) 9

Answer 1

Resposta:

x^2-14-5x=0

x^2-5x-14=0

x^2+2x-7x-14=0

x*(x+2)-7x-14=0

x*(x+2)-7(x+2)=0

(x+2)*(x-7)=0

x+2=0

x-7=0

x= -2

x-7=0

x= -2

x=7

x1= -2, x2= 7

Resposta: x1= -2, x2= 7