Question

The sum of two numbers is 9 . one number is nine less than twice the other. find the two numbers.

Answer 1

Hello!

To solve this problem, we will use a system of equations. We will have one number be x and the other y. We will use substitutions to solve for each variable.

x+y=9
x=2y-9

To solve for the two numbers, we need to solve the top equation. The second equation shows that x=2y-9. In the first equation, we can replace 2y-9 for x and solve.

2y-9+y=9
3y-9=9
3y=18
y=6

We now know the value of y. Now we need to find x. We can plug in 6 for y in the second equation to find x.

x=2·6-9
x=12-9
x=3

Just to check, we will plug these two numbers into the first equation.


3+6=9
9=9

Our two numbers are three and six.

I hope this helps!