xx + x + 5 = 25
x * 11 + x * 1 + 5 = 25
x * (11+1) + 5 = 125
x * 12 = 120
x = 120 : 12
x = 10
xxx - xx - x - 25 = 4430
x * 111 -x * 11 - x * 11 - 25 = 4430
x * 99 - 25 = 4430
x * 99 = 4430 + 25
x * 99 = 4455
x = 4455 : 9
x = 45
xxx + xx + x + x = 992
x * 111 + x * 11 + x * 1 + x * 1= 992
x * ( 111 +11 +1+1) = 992
x * 124 = 992
x = 992 : 124
x = 8
mấy con khác cũng tương tự nhé .
đúng thì nhé
Ta có
xx + x + 5 = 25
x * 11 + x * 1 + 5 = 25
x * (11+1) + 5 = 125
x * 12 = 120
x = 120 : 12
x = 10
xxx - xx - x - 25 = 4430
x * 111 -x * 11 - x * 11 - 25 = 4430
x * 99 - 25 = 4430
x * 99 = 4430 + 25
x * 99 = 4455
x = 4455 : 9
x = 45
xxx + xx + x + x = 992
x * 111 + x * 11 + x * 1 + x * 1= 992
x * ( 111 +11 +1+1) = 992
x * 124 = 992
x = 992 : 124
x = 8
XX + X + 5 = 125
X x 11 + X x 1 + 5 = 125
X x (11 + 1) +5 = 125
X x 12 + 5 = 125
X x 12 = 125 - 5
X x 12 = 120
X = 120 : 12
X = 10