Which line cuts the (y)-axis at ( (0,-10) ) and increases (y) by (28) when (x) increases by (4)?
Answer and explanation
Correct answer: \(y=7x-10\)
The slope is \(\frac{\Delta y}{\Delta x}=\frac{28}{4}=7\). The \(y\)-intercept is \(-10\), so in slope-intercept form \(y=mx+c\), substituting \(m=7\) and \(c=-10\) gives \(y=7x-10\). In \(y=28x-10\), the slope is 28, while in \(y=-7x-10\), \(y\) decreases as \(x\) increases. Exam tip: find slope by calculating \(\Delta y/\Delta x\).
Frequently asked questions
What is the correct answer to this question?
\(y=7x-10\)
Why is this the correct answer?
The slope is \(\frac{\Delta y}{\Delta x}=\frac{28}{4}=7\). The \(y\)-intercept is \(-10\), so in slope-intercept form \(y=mx+c\), substituting \(m=7\) and \(c=-10\) gives \(y=7x-10\). In \(y=28x-10\), the slope is 28, while in \(y=-7x-10\), \(y\) decreases as \(x\) increases. Exam tip: find slope by calculating \(\Delta y/\Delta x\).
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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