Like terms have the same variable part — only the coefficients differ. They're the only terms you can combine.
Quick check
Simplify 3x + 5x − 2x + 4
Combining like terms
- Like terms share the same variable part — 3x and 5x, or 2x²y and −x²y.
- Add or subtract only the coefficients; the variable part is unchanged.
- x and x² are NOT like terms — same letter, different power, so they stay separate.
Your turn
Simplify 4a + 3b − a + 2b.
Watch out
Don't 'simplify' 3x + 4 into 7x. A number and an x-term are not like terms — there is nothing to combine.
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3x + 5x
Same variable x. Add coefficients: 8x.
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3x + 5y
Different variables — they don't combine. Final answer: 3x + 5y.
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2x²y + 3x²y − x²y
All have x²y. Combine: 4x²y.
x and x² are NOT like terms. Same letter, different power.