SAT · Additional Topics in Math · Complex numbers
Question sat-q-00214
Medium Multiple choice Calculator OK
The question
If 2x + 3 = 17, what is the value of x?
- 7
- 8
- 6
- -7
Show answer & worked solution
Answer: 7
Worked solution. Subtract 3 from both sides: 2x = 14. Divide both sides by 2: x = 7.
Why each wrong choice is wrong. The off-by-one and negated answers are common arithmetic-slip distractors. Watch the sign of the constant term when you move it across the equals sign.
Test-day tactic. When the stem is short, do the algebra straight rather than plugging in answer choices — it's faster.
About this question type
A small number of items test complex-number arithmetic. The key fact is i² = −1; multiplication is just FOIL with that substitution. Division by a complex number requires multiplying by the conjugate.
You will see a question shaped like this one on roughly every other official SAT form, typically at a moderate position in the section — solidly within the range that separates a 600-band student from a 700-band student. Treat any miss in this subtopic as a signal to drill the subtopic page before you do another full practice test.