Question

Решите уравнение (3-х)²-x²=15

Answer 1

$(3-x)^2-x^2=15$
$9-6x+x^2-x^2=15$
$9-6x=15$
$-6x=6$
$x=-1$

Answer 2

(3-x)^2-x^2=15
(9-6x+x^2)-x^2=15
9-6x+x^2-x^2=15
9-6x=15
6x=-6
x=-1
Вроде так.