# How do I use substitution to find the solution of the system of equations #4x+3y=7# and #3x+5y=8#?

##### 1 Answer

To use substitution, you would solve one of the equations for x (or y), and then plug it into the other equation for x(or y). You'll find that you will end up with one equation and one variable, which you can solve quite simply using algebra. When you get that answer, you can plug it back into the original equation you started with to get the other variable.

Since these are simultaneous equations, you can actually solve for x or y in either equation- You'll get the same answer either way.

**Solution:**

Equation 1:

Equation 2:

Solving **Equation 1** for

Plugging **Equation 2** :

Now we only have one variable that we can solve for. Solving **Equation 2** :

We've solved for one of the variables! To solve for the other, we plug this back into **Equation 1** to solve for

And we've solved for the other variable. Interestingly, both the x and y values are 1, so

and

Remember that you don't have to follow this exact method to solve this. You can solve either equation for x or y and plug into the other and then plug back into the one you started with, and you should get the same answer.