Answer:
Explanation:
Let the 10s digit = x
Let the units digit = y
x +y = 11 Sum of the digits = 11
10x + y + 45 = 10y + x Reversed number is 45 more than original #
10x - x + y + 45 = 10y We subtracted x from both sides.
9x + y + 45 = 10y Subtract y from both sides.
9x + 45 = 10y - y Combine the right
9x + 45 = 9y
Put x + y = 11 into the equation just found.
9x + 45 = 9(11 - x) divide through by 9
x + 45/9 = 11 - x add x to both sides
2x + 5 = 11 Subtract 5 from both sides
2x = 11 - 5
2x = 6 Divide by 2
x = 6/2
x = 3
x + y = 11
3 + y = 11
y = 11 - 3
y = 8
Now check it out.
the original number is 38
the new number is 83 which the digits are reversed.
83 - 38 = 45 just as it should.