25b-(b-5)=29 25b-b+5=29，24b=24，b= 1。

7x+2 (3x-3) = 207x+6x-6 = 20, 13x = 26x = 2 pairs.

8y-3(3y+2)=6, 8y-9y+6=6 is wrong, it should be 8y-9y-6=6, y=- 12.

2(x+8)=3(x- 1)，2x+ 16=3x-3，2x-3x=-3- 16，- 1x =- 19x = 65438+。

8x=-2(x+4), 8x=-2x-8, 8x+2x=-8, 10x=-8, x= 10 -8 pairs.

Six questions, four questions correctly, 70 points. The mistakes are in brackets. Remember, when you move things, you must change the sign. Keep trying!

Whether the symbols change or remain unchanged after the brackets are removed depends on whether the brackets are preceded by+or-.Not all symbols change.