AlgebraHardSlope of a line reflected across the x-axis
Algebra practice question
In the xy-plane, line ℓ has the equation y = (3/4)x + 2. Line m is the reflection of line ℓ across the x-axis. What is the slope of line m?
Answer: -3/4 or -0.75
Reflecting across the x-axis replaces y with −y: −y = (3/4)x + 2, so y = −(3/4)x − 2 and the slope is −3/4.
Common wrong answers
- If you answered 3/4
- 3/4 leaves the slope unchanged, as a reflection across the y-axis would not either; only the sign flips here.
- If you answered -4/3
- −4/3 is the slope of a perpendicular line.
- If you answered 4/3
- 4/3 inverts without flipping the sign.
More Algebra questions
- Hard
For how many integer values of x is −2 < (x − 5)/3 ≤ 1 true? - Hard
The system 2x + 3y = 6 and 4x + 6y = k has infinitely many solutions. What is the value of k? - Hard
Which of the following is the complete solution set to |x − 4| < 6? - Hard
A student has $40 to spend on notebooks costing $4 each and pens costing $2 each, and wants at least 12 items … - Hard
What is the least whole number of minutes of international calling in a month for which the total monthly cost… - Hard
How many liters of the 30% acid solution did the technician use?
Not affiliated with the College Board. SAT is a trademark of the College Board.