AlgebraEasy–MediumDistributing a negative before solving
Algebra practice question
If 9 − 2(x + 1) = 1, what is the value of x?
Answer: 3
Distribute: 9 − 2x − 2 = 1, so 7 − 2x = 1. Then −2x = −6 and x = 3.
Common wrong answers
- If you answered 4
- 4 comes from 9 − 2x + 2 = 1 — the −2 must be distributed onto the +1 as well.
- If you answered 5
- 5 comes from 9 − 2x − 2 = 1 solved as 2x = 10 (adding 2 and 1 wrongly); 7 − 1 = 6, and 6/2 = 3.
- If you answered -3
- −3 has the wrong sign: −2x = −6 gives x = 3.
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