The Sum of Two Numbers is 4 and Their Difference is 8

The sum of two numbers is 4 and their difference is 8. What are the two numbers? Let's start by calling the two numbers we are looking for x and y.

The sum of x and y is 4. In other words, x plus y equals 4 and can be written as equation A:

x + y = 4

The difference between x and y is 8. In other words, x minus y equals 8 and can be written as equation B:

x - y = 8

Now solve equation B for x to get the revised equation B:

x - y = 8
x = 8 + y

Then substitute x in equation A from the revised equation B and then solve for y:

x + y = 4
8 + y + y = 4
8 + 2y = 4
2y = -4
y = -2

Now we know y is -2. Which means that we can substitute y for -2 in equation A and solve for x:

x + y = 4
x + -2 = 4
X = 6

Summary: The sum of two numbers is 4 and their difference is 8. What are the two numbers? Answer: 6 and -2 as proven here:

Sum: 6 + -2 = 4
Difference: 6 - -2 = 8

Sum Difference Calculator
Do you want the answer to a similar problem? Enter the sum and difference here to find the two numbers:

The Sum of Two Numbers is 4 and Their Difference is 9
Using what you learned on this page, try to figure out the next problem on our list and then go here to check the answer.