Question 253278
10x+y=10y+x+3y
10x-x+y-10y-3y=0
9x-12y=0 multiply by -5
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5(x+y)=70
5x+5y=70 multiply by 9 & add
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-45x+60y=0
45x+45y=630
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105y=630
y=630/105
y=6 answer for the tens digit in the original number.
5(x+6)=70
5x+30=70
5x=70-30
5x=40
x=40/5
x=8
Proof:
10*8+6=10*6+8+3*6
80+6=60+8+18
86=86