The sum of two numbers is 25 while their difference is 11. What are the two numbers?

If a + b = 25 and a - b = 11 as asked, we can solve like this: a - b = 11 => a = 11 + b [Now we have expressed a in terms of b. Let's substitute that information in the first equation.] a + b = 25 => (11 + b) + b = 25 => 11 + b + b = 25 => 11 + 2b = 25 => 2b = 14 => b = 14/2 & b = 7 Substitute the value for b (the 7) into either equation and solve like this: a + b = 25 => a + 7 = 25 => a = 25 - 7 & a = 18 Lastly, substitute your answers into either equation and see if it checks.