SAT · Heart of Algebra · Linear equations in one variable
Question sat-q-00013
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The question
If 3x − 8 = 4, what is the value of x?
- 3
- 5
- 4
- -4
Show answer & worked solution
Answer: 4
Worked solution. Subtract -8 from both sides: 3x = 12. Divide both sides by 3: x = 4.
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
These items present a linear equation in a single variable and ask you to solve for that variable. The variable may appear on both sides; the equation may include nested parentheses, fractional coefficients, or a variable in a denominator that turns out to cancel cleanly. The test occasionally hides a one-step equation inside a sentence-long word problem, where two-thirds of the difficulty is parsing the English.
You will see a question shaped like this one on roughly every other official SAT form, typically at an early position in the section, where missing them carries an outsize penalty because the curve assumes everyone in your band gets them right. Treat any miss in this subtopic as a signal to drill the subtopic page before you do another full practice test.