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A math problem that asks a student to find x on a triangle. A student draws an arrow to the x on one of the triangle's side.

Algebra wouldn't be fun if it were this easy to find x!

It's all about using step-by-step logic to figure out missing numbers.

There's more than one way to find x.

Did you know?

If you see x in an equation (or any letter in place of a number), it just means a number isn't known yet. This unknown number is called a variable in math jargon (mathisfun.com, "Definition of Variable", 2020).

One Always Equals The Other

Two Spidermen point at each other. Each Spiderman represents one side of the equation 3x = 20 - 5. The answer x = 5.

Equation comes from the word equal, so one side of an equation will always be equal to the other side. If you can find the value of one side, you'll know the value of the other.

Flaticon IconWork it out!

Use the clues below to solve this equation:

2x = 12 - 8

  • What's the value of the right side?

  • What number, if you multiply it by 2, will give you the same value of the right side?

Quiz

What's x?

Opposites Attract

Yin and yang symbol. The black & white dots alternate, then change to the opposite of each color.Since both sides of an equation are equal, they'll balance each other out. If you look at one side's symbol and apply the opposite symbol to the other side, you can find the balance to work out the equation.

Flaticon IconThink of it like a seesaw. If the person on one side of the seesaw is on the ground, the other person has to push down on the other side for the seesaw to even out.

So if one side has multiplication? Use division on the other side to work out the balance.

Flaticon IconWork it out!

5x - 3 = 12

You need to isolate x on the left side, so you need to get 5 and 3 to the right side.

Follow the steps below to solve this equation:

  • Move - 3 to the right side, make it + 3, and add it to 12

  • The value of the right side: 12 + 3 = 15

  • Move 5 to the right side and divide it into 15

Quiz

What's x?

Take Action

Two young men working on a math problem. They are amazed to see equations pop out of their notebooks and float in the air.

Who knows what you'll be able to solve next!

Once you're comfortable with these go-to strategies for solving x, you'll be able to do more and more with algebra.

The next time you're doing an algebra equation:

License:

This Byte has been authored by

SB

Steve Birek

Director of Learning Content at Rumie

English

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