Year 7 · Maths · Equality and equivalence · Lesson 3
Like terms and equivalence
Collect like terms to solve equations, and decide whether expressions are equivalent by simplifying, expanding and testing values.
27-minute video lesson
Teaching, worked examples and 20 practice questions solved step by step.
Watch free for a monthWhat your child will learn
- Collect like terms in equations
- Solve equations after simplifying
- Understand equivalent expressions
- Test for equivalence
- Form and solve equations from shapes and problems
The method
- Collect like terms first.
- Then solve using the inverse operation.
- Equivalent? Simplify both, or test values.
- One counter-example shows they are NOT equivalent.
Key words: like terms, equivalent, equation, expression, simplify.
Worked examples
The first three practice questions from the lesson, with every step.
Question 1
Solve 2x + 4x = 24.
- Step 1: 2x + 4x = 6x
- Step 2: Write the equation
- Step 3: Divide both sides by 6
- Step 4: Check your answer
Answer: x = 4
Question 2
Solve 5x + 3x = 64.
- Step 1: 5x + 3x = 8x
- Step 2: Write the equation
- Step 3: Divide both sides by 8
- Step 4: Check your answer
Answer: x = 8
Question 3
Solve 9a − 4a = 45.
- Step 1: 9a − 4a = 5a
- Step 2: Write the equation
- Step 3: Divide both sides by 5
- Step 4: Check your answer
Answer: a = 9