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Intro to equations

Learn what an equation is and what it means to find the solution of an equation.

What is an equation?

An equation is a statement that two expressions are equal. For example, the expression 5+3 is equal to the expression 6+2 (because they both equal 8), so we can write the following equation:
5+3=6+2
All equations have an equal sign (=). The = sign is not an operator like addition (+) or subtraction () symbols. The equal sign doesn't tell us what to do. It only tells us that two expressions are equal. For example, in:
62=3+1
The sign tells us what to do with 6 and 2: subtract 2 from 6. However, the = sign does not tell us what to do with 62 and 3+1. It only tells us that they are equal.
Let's make sure we know the difference between an expression and an equation.
Which of these is an equation?
Choose 1 answer:

True equations

All of the equations we just looked at were true equations because the expression on the left-hand side was equal to the expression on the right-hand side. A false equation has an =, but the two expressions are not equal to each other. For example, the following is a false equation.
2+2=6
When we see an equation that's not true, we can use the not equal sign () to show that the two expressions are not equal:
2+26
Let's make sure we understand what a true equation is.
Which of these are true equations?
Choose all answers that apply:

Solutions to algebraic equations

All of the equations that we've looked at so far have included only numbers, but most equations include a variable. For example, the equation x+2=6 has a variable in it. Whenever we have an equation like this with a variable, we call it an algebraic equation.
For an algebraic equation, our goal is usually to figure out what value of the variable will make a true equation.
For the equation x+2=6, notice how x=4 creates a true equation and x=3 creates a false equation.
True equationFalse equation
x+2=64+2=?66=6x+2=63+2=?656
Notice how we use the symbol =? when we're not sure if we have a true equation or a false equation.
The value of the variable that makes a true equation is called a solution to the equation. Going back to our example, x=4 is a solution of x+2=6 because it makes the equation true.

Let's try a few problems

Problem 1
Select the solution to the equation.
3+g=10
Choose 1 answer:

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