By Emma Davis
Edited by Sophia Layton
Say you’re given an equation in the form ax + b = c. How would you go about solving this for x?
Think of it like you are undoing all the operations in the equation.
Let’s use 3x + 5 = 20 as an example. To solve for x, you want to have x alone on the left side of the equation. So the first step is to undo the addition or subtraction, which in this case, would be the + 5.
To undo addition, subtract the number being added from both sides of the equation. To undo subtraction, add the number being subtracted to both sides.
3x + 5 = 20
- 5 - 5
3x = 15
You should be left with 3x = 15. Now, the next step is to undo any multiplication or division. For this equation, we need to get rid of the 3 that is multiplying the x.
To undo multiplication, divide each side by the coefficient (the number next to the variable- the one that is multiplying it. In this case, the coefficient is 3). To undo division, multiply each side by the divisor.
3x = 15
x = 5
You should be left with x = 5. Congrats! You’ve solved it for x. To check your answer, insert the x value (what x ends up equal to) in place of x in the original equation. If the equation is true, you are correct!
3(5) + 5 = 20
15 + 5 = 20
20 = 20
Here are some more examples for reference!