Question

c) (x - 1) (2x + 1) = (x - 1)(x + 4).
Alguém me ajuda

Answer 1

Resposta:

Explicação passo-a-passo:

$(x - 1) (2x + 1) = (x - 1)(x + 4)\\\\x.2x+x.1-1.2x-1.1=x.x+x.4-1.x-1.4\\\\2x^{2}+x-2x-1=x^{2}+4x-x-4\\\\2x^{2}-x-1=x^{2}+3x-4\\\\2x^{2}-x^{2}-x-3x-1+4=0\\\\x^{2} -4x+3=0\\x=3\\\\ou\\\\x=1$