# How do you evaluate expressions when you have more than one variables?

##### 1 Answer

There are many methods that you can use for solving equations with two variables. Here are two simple methods that I find easy for solving linear equations with two variables.

Remember, you always need at least two equations to solve equations with two variables

**1. Substitution**

Here, you basically write one equation in terms of one of its variables, and then substitute that value in the second equation.

**Example:**

Solving two equations:

Now, I'll write the first equation in terms of

Now, I can substitute this value of

Thus,

**2. Elimination**

Here, you:

**a.** First, multiply one or both equations so that either variable have the same coefficients.

**b.** Then, add *or* subtract one equation to/from another so that one of the variable term is **completely eliminated.**

**c.** Substitute the value you find out in any other equation to find the value of the other variable.

**Example:**

Solving two equations:

Looking at the two equations, I can make out that by multiplying the first equation by

The first equation becomes:

When I subtract the second equation from the above equation, the terms with

That is,

Substituting the value of

**SIMILARLY, YOU CAN EVALUATE EXPRESSIONS WITH MORE VARIABLES WITH MORE NUMBER OF EQUATIONS. **