maths(2)(急急急急急.....)

1. 2(b+2)/3-3/4=2b+1/4
8(b+2)-9/12=8b+1/4
8b+16-9=24b+3
b=4/16
b=1/4

2. 3-[5x-(2x-3)] = x-16
3-(5x-2x+3)=x-16
3-5x+2x-3=x-16
-3x=x-16
-4x=-16
x=4

3. -2[5(3-x)+3]-1 = 3[2(3-x)+3]
-2(15-5x+3)-1=3(6-2x+3)
-30+10x-6-1=18-6x+9
10x-37=27-6x
16x=64
x=4

1. 2b+4/3 - 3/4 - 1/4 = 2b
6b+15/12-9/12-3/12=2b
8b+4=24b
4=16b
6=4/16
b=1/4

2. 3=x-16+[5x-(2X-3)
19=x+5x-2x+3
19=4X+3
16/4=4x/4
4=x

3. -2[15-5x+3]-1=3[6-2x+3]
-30+10x-6-1=18-6x+9
-37+10x=27-6x
10x+6x=27+37
16x=64
x=4