1.3b+(5-7b)
2.-(8c-4)-4
3.3(8a-4)+6a
4.7p-2(3p-1)
5.x(x-(2x-4))
7 класс.

1. 3b+5-7b=-4b+5; 2. -8c+4-4=-8c; 3. 24a-12+6a=30a-12; 4. 7p-6p+2=p+2; 5. x(x-2x+4x)=x²-2x²+4x²=3x².