Question

the sum of two numbers is 3 more than 3 times of the smaller if the difference of the numbers is 5 find the number

Answer 1

let x be the smaller number
$x + y = 3(x + 3) \\ x + y = 3x + 9 \\ 2x - y + 9 = 0$
and
$y - x = 5 \\ y = x + 5$
put in the the first equation,
$2x - x - 5 + 9 = 0 \\ x = - 4 \\ y = 1$