Bài tập toán số giải phương trình

Bài `1:` 

`a) 3x - 2 = 2x - 3`

`<=> x = -1`

`b) 2x + 3 = 5x + 9`

`<=> 3x = -6`

`<=> x = -2`

`c) 5 - 2x = 7`

`<=> -2x = -2`

`<=> x = 1`

`d) 10x + 3 - 5x = 4x + 12`

`<=> 5x + 3 = 4x + 12`

`<=> x = 9`

Bài `2:`

`a) (3x + 2)/2 - (3x + 1)/6 = 5/3 + 2x`

`<=> (9x + 6 -(3x+1))/6 = 5/3 + 2x`

`<=> (6x+5)/6 = 5/3 + 2x`

`<=> 6x + 5 = 10 + 12x`

`<=> 6x = -5`

`<=> x = -5/6`

`b) (4x + 3)/5 - (6x - 2)/7 = (5x + 4)/3 + 3`

`<=> (7(4x + 3) - 5(6x - 2))/35 = (5x + 13)/3`

`<=> (-2x + 31)/35 = (5x+13)/3`

`<=> 3(-2x + 31) = 35(5x+13)`

`<=> -6x + 93 = 175x + 445`

`<=> -362 = 181x`

`=> x = -2`

`c) (x+4)/5 - x + 4 = -x/3 - (x-2)/2`

`<=> (-4x + 24)/5 = (-5x + 6)/6`

`<=> 6(-4x + 24) = 5(-5x + 6)`

`<=> -24x + 144 = -25x + 30`

`<=> x = -114`

`d) (5x + 2)/6 - (8x -1)/3 = (4x + 2)/5 - 5`

`<=> (5x + 2 - 16x + 2)/6 = (4x + 2 - 25)/5`

`<=> (-11x + 4)/6 = (4x - 23)/5`

`<=> 5(-11x + 4) = 6(4x - 23)`

`<=> -55x + 20 = 24x - 138`

`<=> 158 = 79x`

`<=> x = 2`