If (y=ax-5) and (y=4x+7) have equal slopes, what is (y) on the first line at (x=2)?
Answer and explanation
Correct answer: 3
In the form \(y=mx+c\), the coefficient of \(x\) is the slope. Since the two lines have equal slopes, \(a=4\). Substituting \(x=2\) in the first line gives \(y=4\times2-5=3\). Option 4 is the value of the slope, not the value of \(y\). Exam tip: first equate the slopes to find the unknown coefficient, then substitute the given value of \(x\).
Frequently asked questions
What is the correct answer to this question?
3
Why is this the correct answer?
In the form \(y=mx+c\), the coefficient of \(x\) is the slope. Since the two lines have equal slopes, \(a=4\). Substituting \(x=2\) in the first line gives \(y=4\times2-5=3\). Option 4 is the value of the slope, not the value of \(y\). Exam tip: first equate the slopes to find the unknown coefficient, then substitute the given value of \(x\).
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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