1, ( x - 12 ) -15 = ( 20 - 7 ) - ( 18 +x )
( x- 1 2) - 15 = 3 - (18 +x)
( x - 12) + (18 + x) = 3 + 15
x - 12 + 18 +x = 18
2x + 6 = 18
2x = 18 - 6
2x = 12
x = 12 : 2
x = 6
2; ( 3x- 17 ) + 2 ( 5- 2x) + 5x = 19
3x - 17 + 10 - 4x + 5x = 19
4x - 7 = 19
4x = 19 + 7
4x = 26
x = 26 : 4
x = 13/2
a,(x-12)-15=(20-7)-(18+x)
x-12-15=3-18-x
x-27=-15-x
x+x=27-15
2x=12
x=6
b,(3x-17)+2(5-2x)+5x=19
3x-17+10-4x+5x=19
3x-4x+5x=19+17-10
4x=26
x=6.5
a,(x-12)-15=(20-7)-(18+x)
x-12-15=3-18-x
x-27=-15-x
x+x=27-15
2x=12
x=6
b,(3x-17)+2(5-2x)+5x=19
3x-17+10-4x+5x=19
3x-4x+5x=19+17-10
4x=26
x=6.5