Definition: An equation is a mathematical statement that two expressions are equal, joined by an equal sign, and it may be true or false depending on the variable.
What is an equation?
An equation says that the left side and the right side have the same value. Think of a balanced scale: whatever sits on one side matches the other.
What is a solution?
A solution is a value of the variable that makes the equation true. For x + 8 = 21, the solution is 13, because 13 + 8 = 21. Try 10 and you get 18, which does not equal 21.
How do you solve a one-step equation?
Use the inverse operation on both sides to keep the scale balanced.
- To undo addition, subtract.
- To undo multiplication, divide.
Solve 7n = 91. Divide both sides by 7. Then n = 13. Check: 7 x 13 = 91.
Which mistake is common?
Changing only one side. If you subtract 8 from the left side alone, the equality breaks. Whatever you do to one side, do to the other.
Why does it matter?
Equations model real situations, like finding how many hours a job takes or how much each ticket costs.