Question

Х(х+7)=(2-х)(х+2) Решите уравнение

Answer 1

х(х+7)=(2-х)(х+2)
x²+7x=2x+4-x²-2x
x²+7x=4-x²
2x²+7x-4=0
D=49+32=81
$x_{1}= \frac{-7+9}{4} = \frac{1}{2}$
$x_{2}= \frac{-7-9}{4} = -4$