Question

The sum of two numbers is 21. Trice the larger number minus twice the smaller number is 18. find the numbers​

Answer 1

15, 6

Explanation:

x = large number

y = small number

1) x + y = 21

2) x = 21 - y

3) 2x - 2y = 18

substitute equation 2 into equation 3 so you have an expression all in terms of y, then you can solve for y.

2(21-y) - 2y = 18

42 - 2y - 2y = 18

-4y = -24

y = -24/-4 = 6

Now you can solve for x, plug y=6 into equation 1 :

x + 6 = 21

x = 21 - 6 = 15