Slope-Intercept Practice

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Question 1

Given that the Slope-Intercept form for an equation of line is:

y = mx + b

Which of the line below (labeled A, B, C and D) is the graph of:

y = x -2

Multiple lines with the label A, B,C, D


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Select and check your answer...

A. Line A
B. Line B
C. Line C
D. Line D

Step by Step Solution

  • Lesson Icon

    Step 1

    To solve this question, we should know that:

    m = slope of the line
    b = y-intercept of the line

    A line will slant upwards to the right for m > 0 and the slants upwards to the left for m < 0.

    You can look at the pictures below to understand better.

    • positive slope
    • negative slope
    slope-intercept form of a line
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    Step 2

    Next, y-intercept is the y-coordinate of the point that the line crosses the y-axis.

    The picture on the right will help you to understand this better.

    x and y intercepts
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    Step 3

    With what you have learned in Step 1 and Step 2, we can start to label the slope and y-intercept for all the lines as shown in the picture.

    Now, from the given equation:

    y = x -2
    => y = 1x -2

    We can see that:

    slope = m = 1 (hence, m >0)
    y-intercept = b = -2

    From this, only line C has m > 0 and y-intercept = -2.

    Clearly, the answer is C.

    lines labeled with slope and y-intercept