Question

x²-8x=9 alguém me fala pelo amor de dejs

Answer 1

$x^2-8x-9=0 \\\\\delta =(-8)^2-4\times 1\times(-9) \\\\\delta =64+36 \\\\\delta =100 \\\\ x_1= \frac{8+\sqrt(100)}{2} \\\\ x_1= \frac{8+10}{2} \\\\ x_1= 9 \\\\ x_2= \frac{8-\sqrt(100)}{2} \\\\ x_2= \frac{8-10}{2} \\\\ x_2= -1$