2(3x+5)-5(2x-6)=20
6x+10-10x+30=20
-4x=20-40
-4x=-20
x=5
2(6x-8)-3(x-1)=23
12x-16-3x+3=23
9x=23+13
9x=36
x=4
5(24-3x)=3(x+3)-15
120-15x=3x+9-15
-15x-3x=-6-120
-18x=-126
x=7