Question

6. Rezolvaţi ecuația (x + 2)^2 = 6x +7,x € R.​

Answer 1

$(x + 2) ^{2} = 6x + 7 \\ x ^{2} + 4x + 4 = 6x + 7 \\ {x}^{2 } - 2x - 3 = 0$

∆=b^2-4ac=(-2)^2-4×1×(-3)=4+12=16

$x1 = \frac{ - b + \sqrt{16} }{2a} = \frac{2 + 4}{2} = \frac{6}{2} = 3$

$x2 = \frac{ - b - \sqrt{16} }{2a} = \frac{2 - 4}{2} = \frac{ - 2}{2} = - 1$