Question

me ajudem 2(x²-1)=x²+7 ....

Answer 1

2x² -2 = x² +7
x² - 9= 0
x = 0 +- raiz 0² -4*1*(-9)/2*1
x = 0 +- raiz 36 / 2
x = +- 6/2
x1 = +3
x2 = -3

Answer 2

 2(x²-1)=x²+7
2x² -2 =x² +7
2x²-x² -2 -7=0
x² -9=0
x²= +9
x=√9
x=3