# Substitution method: The diff. of 2 numbers is 16....

#### bryansherburne

##### New member
i need help on math. The problem is, the difference between two numbers is 16. three times the larger number is 7 times the smaller. what are the numbers?

#### galactus

##### Super Moderator
Staff member
Re: substitute methode

The difference of two numbers is 16: x-y=16

3 times the larger is equal to 7 times the smaller: 3x=7y

You have two equations. Can you use the sub method to solve now?.

#### bryansherburne

##### New member
Re: substitute methode

i don't know because we usually have prblems pu like this: 2x-3y=86, then on the bottom we have something like this: 2x+y= -24 and the itll come ou to 2y=62 and then you have to divide and then it comes out to y=31. Do you know how to do problems like this?

#### o_O

##### Full Member
Re: substitute methode

As galactus said, you have:
x - y = 16
3x = 7y

You can use the second line to solve for x in terms of y, and plug it back into your first line so that you only have one variable to solve for.

#### bryansherburne

##### New member
Re: substitute methode

thanks the example of the problem helped thank you very much!!!! :mrgreen: