AlgebraMediumSlope of a line through points given in terms of a parameter
Algebra practice question
In the xy-plane, a line passes through the points (a, 0) and (0, 2a), where a is a positive constant. What is the slope of the line?
Answer: -2
Slope = (2a − 0)/(0 − a) = 2a/(−a) = −2.
Common wrong answers
- If you answered 2
- 2 has the wrong sign: the run is −a.
- If you answered -1/2
- −1/2 is run over rise.
- If you answered -2a
- The a cancels; the slope does not depend on a.
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