(x+24)×30=900
раскроем скобки
30x+720 = 900
30x-180 = 0
30x = 180
x = 6
x+24×30=900
x+720=900
x-180 = 0
x = 180
x×20-240=360
x×20=360+240
x×20=600
x=600/20
х=30
(x+24)×30=900
раскроем скобки
30x+720 = 900
30x-180 = 0
30x = 180
x = 6
x+24×30=900
x+720=900
x-180 = 0
x = 180
x×20-240=360
x×20=360+240
x×20=600
x=600/20
х=30