xin loi minh nham 235 thanh 285, sua lai nha ket qua bang 100
(285 - x) - 81 = 54
285 - x = 54 + 81
285 - x = 135
x = 285 - 135
x = 150
\(\left(235-x\right)-81=54.\)
\(235-x=54+81\)
\(235-x=135\)
\(x=235-135\)
\(x=100\)
(235 - x) - 81 = 54
(235 - x) = 54 + 81
(235 - x) = 135
x = 235 - 135
x = 100