Question 134766
The 10 is a multiplier for the tens digit value. This problem 's answer is 35 & the when 18 is added the numbers reverse thus: 35+18=53
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10x+y=7y or 10x=7y-y or 10x=6y or x=6y/10
now replace x in the other equation & solve for y
10x+y+18=10y+x
6y+y+18=10y+6y/10
7y-10y-6y/10=-18
-3y-6y/10=-18
(-3y*10-6y)/10=-18
-30y-6y=-18*10
-36y=-180
y=-180/-36
y=5 answer.
10x=6*5
10x=30
x=30/10
x=3 answer.
proof:
10x+y=7y 
10*3+5=7*5
30+5=35
35=35