Ответ:

1) 4·x²-(2·x-1)²=15

4·x²-(4·x²-4·x+1)=15

4·x²-4·x²+4·x-1=15

4·x=15+1

x=16:4=4.

2) 9·x²-1=(3·x-2)²

9·x²-1=9·x²-12·x+4

9·x²-9·x²+12·x=4+1

12·x=5

x=5/12.

3) (3·x+1)²-(3·x-1)²=11·x+1,2

(3·x+1-3·x+1)·(3·x+1+3·x-1)=11·x+1,2

2·6·x=11·x+1,2

12·x-11·x=1,2

x=1,2.

4) (5+2·y)·(y-3)-2·(y-1)²=0

5·y-15+2·y²-6·y-2·(y²-2·y+1)=0

2·y²-y-15-2·y²+4·y-2=0

3·y=17

y=17/3.