Ответ: а 2х + 7 = 3х - 2 (3х - 1)
2х + 7 = 3х - 6х + 2
2х - 3х + 6х = 2 - 7
5х = - 5
х = -5/5
х = -1.
б 2-(х+3)=2(х-5)
2-х-3=2х-10
2+10-3=2х-х
9=3х
Х=3
в 5х + 3 = 7х - 5 * (2х + 1)
5х + 3 = 7х - 10х - 5
5х + 3 = -3х - 5
5х + 3х + 3 = -5,
8х + 3 = -5.
8х = -5 - 3,
8х = -8.
х = -8 / 8,
х = -1.
г 7 - х(3+х) = (х+2)(5-х)
7-3х - х^2=5x+10-2x-x^2
7-3x-3x=10-7
-6x=3
x=-(1/2) или х=-0,5