The sum of two numbers is twice their difference. The larger number is 7 more than twice the smaller. Find the numbers.
let x and y be two required numbers. Let x be the larger number in concern.
1) the sum of two numbers is twice their difference
$\displaystyle x+y = 2 (x-y) $
2) the larger number is 7 more than twice the smaller.
$\displaystyle x = 2y + 7 $
you now have two equations and two unknown. Use substitution to solve.
P.S. this is wrong section. If this is a pre-calc problem you should have posted it in pre-calc section.