Question 380475
let the number be xy.
x ten's place
y units place
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x+y = 12......................1
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10x+y is the number
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10x+y+18= 10y+x
10x-x+y-10y=-18
9x-9y=-18
/2
x-y =-2........................2
add 1 & 2
2x=12-2
2x=10
/2
x=5
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x+y =12
so y=7
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the number is 57
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m.ananth@hotmail.ca