Question

x²-4x-5=0 resposta exata

Answer 1

x = - (-4) +- raiz (-4)² -4*1*(-5) /2*1
x =4 +- raiz 16 +20 /2
x = 4 +-raiz 36 / 2
x = 4 +-6/2
x1 = 4+6 /2
x1 = 10/2 => 
x1 = 5


x2 = 4 -6/2
x2 = -2/2 =>
x2 = -1