Question 1Mid
A 40-liter mixture is acid. How many liters of a acid solution must be added to make the resulting mixture acid?
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Answer: C — 20
If liters are added, then . This gives , so .
Study on the flySATMathLinear equations in one variable
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Linear equations in one variable — SAT practice questions
- 151 practice questions in the app
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What this topic is
Linear equations in one variable contain a single unknown raised only to the first power, and solving them means isolating that unknown with inverse operations.
Questions often add a twist: instead of asking for x, they ask for the value of a related expression, which can sometimes be found by scaling the whole equation rather than solving for x first. Other items ask when an equation has no solution or infinitely many solutions; that happens when the x terms cancel, leaving a false statement or a true one, and a constant must be chosen to make the coefficients match.
Mixture word problems also lead to these equations.
Sample questions
Pick an answer to see whether it is right — nothing is saved, and nothing needs an account.
Question 2Easier
If , what is the value of ?
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Answer: B — 15
Notice that . Since , we get .
Question 3Easier
In the given equation, is a constant. The equation has infinitely many solutions. What is the value of ?
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Answer: B — 6
Expanding the left side gives . Matching both sides requires and , and both conditions give .
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Practice 151 Linear equations in one variable questions in the app
More SAT topics
Math
- Linear equations in two variables
- Linear functions
- Systems of two linear equations in two variables
- Linear inequalities in one or two variables
- Equivalent expressions
- Nonlinear equations and systems
- Nonlinear functions
- Ratios, rates, proportional relationships, and units
- Percentages
- One-variable data: distributions and measures
- Two-variable data: models and scatterplots
- Probability and conditional probability
- Inference from sample statistics and margin of error
- Evaluating statistical claims
- Area and volume
- Lines, angles, and triangles
- Right triangles and trigonometry
- Circles
Harder than the exam: SAT Challenge · Competition-style problems
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