Question

Решите уравнения: х²=-9х-8 х²-20х=-5х-13-х²

Answer 1

$x^{2} +9x+8=0 \\ D=81-32=49 \\ \sqrt{D}=7 \\ x_{1}= \frac{-7+7}{2}=0 \\ x_{2}= \frac{-7-7}{2}=-7$

$x^{2} -20x+5x+13+ x^{2} =0 \\ 2 x^{2} -15x+13=0 \\ D=121 \\ \sqrt[n]{D}=11 \\ x_{1}= \frac{15+11}{4}=6.5 \\ x_{2}= \frac{15-11}{4}=1$