What is an Identity Equation? | Printable Summary

One number definitely equals itself, so 27 = 27 is a 100% true statement
As long as the two sides of the equation look identical, it's still an identity equation!
Even when both sides don't look the same, simplifying both sides may show you that the sides are equal
Even when there are variables in the equations, you can get an identity if both sides are identical
Sometimes, the sides may look nothing alike but will still simplify to show an obvious identity equation

1. Let's start with an example containing just one number
2. One number definitely equals itself, so this is a 100% true statement
1. In other words, identity equations are always true statements
1. We can include additions signs and anything else we want to, but if the two sides of the equation look identical, it's still an identity equation
1. Even though both sides don't look the same, both sides simplify to 27!
1. Even when there are variables in the equations, you can get an identity if both sides are identical
1. Here we plugged '2' in for 'x'
2. 6•2=12
1. Here we plugged '3' in for 'x' to show that we can pick any number for 'x' and we will still get a true statement
2. 6•3=18
1. Here is another example containing a variable, but the sides of the equations aren't identical
2. Distribute the 3 and you'll see this, too, is an identity equation!
1. Here's an extreme example of an identity equation where both sides look nothing alike
2. You'll again want to use the distributive property to simplify the right side