a) 156 - ( x + 61 ) = 82
x - 61 = 156 - 82
x - 61 = 74
x = 74 + 61
x = 135
b) 420 + 65 x 4 = ( x + 175 ) : 5 + 10
420 + 260 = ( x + 175 ) : 5 + 10
( x + 175 ) : 5 + 10 = 420 + 260
( x + 175 ) : 5 + 10 = 680
( x + 175 ) : 5 = 680 - 10
( x + 175 ) : 5 = 670
x + 175 = 670 x 5
x + 175 = 3350
x = 3350 - 175
x = 3175
156-(x+61)=82 420+65x4=(x+175):5+10
x+61=156-82 420+260=(x+175):5+10
x+61=74 680=(x+175):5+10
x=74-61 (x+175):5+10=680
x=13 (x+175):5=680-10
(x+175):5=670
x+175=670x5
x+175=3350
x=3350-175
x=3175
đúng nha
thks trước
156 - ( x + 61 ) = 82
x = 156 - 82 - 61
x = 74 - 61
x = 13
420 + 65 x 4 = (x + 175) : 5 + 10
420 + 260 = (x + 175) : 5 + 10
680 = (x + 175) : 5 + 10
(680 - 10)x 5= x + 175
670 x 5= x + 175
3350 = x + 175
x = 3350 - 175
x = 3175