The Sum of Two Numbers is 8 and Their Difference is 99

The sum of two numbers is 8 and their difference is 99. 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 8. In other words, x plus y equals 8 and can be written as equation A:

x + y = 8

The difference between x and y is 99. In other words, x minus y equals 99 and can be written as equation B:

x - y = 99

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

x - y = 99
x = 99 + y

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

x + y = 8
99 + y + y = 8
99 + 2y = 8
2y = -91
y = -45.5

Now we know y is -45.5. Which means that we can substitute y for -45.5 in equation A and solve for x:

x + y = 8
x + -45.5 = 8
X = 53.5

Summary: The sum of two numbers is 8 and their difference is 99. What are the two numbers? Answer: 53.5 and -45.5 as proven here:

Sum: 53.5 + -45.5 = 8
Difference: 53.5 - -45.5 = 99

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 9 and Their Difference is 1
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.