The line (y=(2r-5)x+(r+1)) passes through the origin. What is (r)?
Answer and explanation
Correct answer: -1
A line has the form y=mx+c, where c is its y-intercept. For the line to pass through the origin (0,0), its y-intercept must be 0. Hence, r+1=0, so r=-1. For example, if r=1, the y-intercept is 2, so that option is incorrect. Exam tip: In questions involving the origin, directly substitute x=0 and y=0.
Frequently asked questions
What is the correct answer to this question?
-1
Why is this the correct answer?
A line has the form y=mx+c, where c is its y-intercept. For the line to pass through the origin (0,0), its y-intercept must be 0. Hence, r+1=0, so r=-1. For example, if r=1, the y-intercept is 2, so that option is incorrect. Exam tip: In questions involving the origin, directly substitute x=0 and y=0.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Introduction to Polynomials. Topic: Slope and y-intercept.
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