How to answer it
- Distribute and simplify.
- Isolate the variable with inverse operations.
- Substitute your answer back to check.
Worked example
An original question in the ACT format, already answered.
ACT MathWorked example
3(2x − 1) = 21
What is the value of x?
- A3
- B11/3
- C4
- D6
Answer: C. Distribute: 6x − 3 = 21. Add 3: 6x = 24, so x = 4. Choice B forgets to distribute the 3 to the −1.
The most common trap
Distributing to the first term only. The 3 multiplies both 2x and −1.
Practice it
Hourly Prep’s daily sets mix algebra with the rest of ACT Math, and send more of it your way when it’s a weak spot. See how the ACT prep plan works, or browse the other ACT skill guides.