Without algebra:
a number consist of two digits of which ten's digit eceeds the unit digit by 7.
So it's either 70, 81 or 92
the numbers itself is equal to 10 times the sum of digits.find the number.
So it's 70 since 7+0=7 and 10 times 7 is 70.
With algebra:
Solve that and get t=7, u=0
Edwin