the sum of two numbers is 20 and the difference is 4

Answer 1

Write a system of equations and use the elimination method

x + y = 20 (sum of 2 numbers is 20)

x - y = 4 (the difference of 2 numbers is 4)

2x = 24 (add your 2 equations together, which eliminates y)

x = 12 (solved for x)

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(12) + y = 20 (plug in 12 for x and solve for y)

y = 8

Answer: The two numbers are 12 and 8

Answer 2

One method to solve:

We know there are 2 different numbers that add up to 20. We also know that the difference between the two numbers is 4.

We can divide 20 by 2 to get 10 which would be the combination if there was no difference. Then we can divide the difference (4) by 2 to get 2. The answers are then 10 +/- 2 which is 12 and 8.