3х+2(5х+7)=40
3x + 10x + 14 = 40
3x + 10x = 40 – 14
13x = 26
x = 2
3(8х-9)-15х=0
24x – 27 – 15x = 0
24x – 15x = 0 + 27
9x = 27
x = 3
3х+2(5х+7)=40
3x + 10x + 14 = 40
3x + 10x = 40 – 14
13x = 26
x = 2
3(8х-9)-15х=0
24x – 27 – 15x = 0
24x – 15x = 0 + 27
9x = 27
x = 3