3(3х + 5) - 5(х+1) = 15 9х +15 - 5х -5 = 15 9х -5х = -15 + 5 +15 4х = 5 х=1,25
(3x+5)3-5(x+1)=3*5 9x+15-5x-5=15 4x+10=15 4x=5 x=5/4