A two-digit number is twice the sum of its digit. If the tens digit is 7 less than the unit digit, find the number. Let x= the unit digit Then y= the tens digit <span>And 10y+x= the number
</span>x+y= the sum of the digits <span>Now we are told that 10y+x=2(x+y) ------1st equation </span> <span>We are also told that y=x-7 ----------- 2nd Equation </span> <span>So our equations to solve are: </span> (1) 10y+x=2(x+y) <span>(2) y=x-7 </span>
