ACT · Coordinate Geometry · Lines, slopes, and intercepts
Question act-q-00396
Medium Multiple choice No calculator
The question
What is the slope of the line passing through (0, 0) and (-4, -1)?
- -0.25
- 4
- 0.25
- 0.75
Show answer & worked solution
Answer: 0.25
Worked solution. Slope = (y₂ − y₁) / (x₂ − x₁) = (-1 − 0) / (-4 − 0) = -1 / -4 = 0.25.
Why each wrong choice is wrong. Reversing the subtraction order in the numerator without doing the same in the denominator gives the negative of the slope — a common slip.
Test-day tactic. Pick which point is (x₁, y₁) and which is (x₂, y₂) before computing, and stick with the choice. The order doesn't matter as long as it's consistent.
About this question type
Items test the slope formula, the slope-intercept and point-slope forms, and the slope rules for parallel (equal) and perpendicular (negative reciprocal) lines.
You will see a question shaped like this one on roughly every other official ACT 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.