Пошаговое объяснение:
1) 3х+3х= –2–7х
6х+7х= –2
13х= –2
х= –2/13
2) 9=5(х+9)
5(х+9)=9
5х+45=9
5х=9–45
5х= –36
х= –36/5
х= –7,2
3) 7(–3+2х)= –6х–1
–21+12х= –6х–1
12х+6х= 21–1
18х=20
х=20/18
х=10/9
х=1цел 1/9
4) 3х–2–3(х+5)= –(2–х)–5
3х–2–3х–15= –2+х–5
–17–х= –7
–х= –7+17
–х=10
х= –10
