Question

1)3.(x-4)-(8-x)=12

2)4.(x-5)-3.(x-7)=-9

3)7.(x-3)-5.(3-x)=11x-5

4)-5.(2-x)+4.(x-3)=10x

Answer 1

1/ 3(x - 4) - (8 - x) = 12 => 3x - 12 - 8 + x = 12 => 4x = 32 => x = 8

2/ 4(x - 5) - 3(x - 7) = -9 => 4x - 20 - 3x + 21 = -9 => x = -10

3/ 7(x - 3) -5(3 - x) = 11x - 5 => 7x - 21 - 15 + 5x = 11x - 5 => x = 31

4/ -5(2 - x) + 4(x - 3) = 10x => -10 + 5x + 4x - 12 = 10x => x = -22

Answer 2

1) 3.(x-4)-(8-x) = 12

=> 3x-12-8+x = 12

=> 4x - 20 = 12

=> 4x = 12 +20 = 32

=> x = 32: 4 = 8

2) 4.(x-5)-3(x-7) = -9

=> 4x-20-3x+21 = -9

=>x +1 = -9

=>x = -9-1= -10

3) 7.(x-3)-5(3-x) = 11x-5

=> 7x-21-15+5x = 11x -5

=> 12x - 36 = 11x -5

=> 12x-11x = -5+36

hay x = 31

4) -5.(2-x)+4.(x-3) = 10x

=> -10+5x+4x-12 = 10x

=> -22 + 9x = 10x

=> -22 = 10x -9x

hay x = -22

XONG