Question

x ao quadrado=x+12 2x ao quadrado=-12x-18

Answer 1

$x^{2} = x + 12 \\ x^{2} - x - 12 = 0 \\ \\ a = 1, b = -1, c = -12 \\ \\ \Delta = b^2 - 4 * a * c \\ \Delta = (-1)^2 - 4 * 1 * (-12) \\ \Delta = 1 + 48 = 49 \\ \\ x = \frac{-b\pm \sqrt{\Delta} }{2*a} \\ \\ x = \frac{-(-1)\pm \sqrt{49} }{2*1} \\ \\ x = \frac{1\pm7}{2} \\ \\ x' = \frac{1+7}{2} = \frac{8}{2} = 4 \\ \\ x'' = \frac{1-7}{2} = \frac{-6}{2} = -3$

$2 x^{2} = -12x - 18 \\ 2 x^{2} + 12x + 18 = 0 \\ x^{2} + 6x + 9 = 0 \\ \\ a = 1, b= 6, c= 9 \\ \\ \Delta = 6^{2} - 4 * 1 * 9 \\ \Delta = 36 - 36 = 0$

$x = \frac{-6\pm \sqrt{0} }{2} \\ \\ x' = x'' = \frac{-6}{2} = -3$

Answer 2

x^2 = x+12
x^2-x-12=0
∆=1+48
∆=49
x= 1+ou -√49
x'=1+7/2
x'= 8/2=4
x"=1-7/2=-6/2
x"= -3

2x^2= -12x-18
2x^2+12x+18=0
∆= 144-144
∆=0
x'=x"= -12/4=-3