Big Ideas Math Algebra 2, 2014
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Big Ideas Math Algebra 2, 2014 View details
1. Parent Functions and Transformations
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Exercise 62 Page 10

You'll need to substitute 0 for both variables and solve.

x-intercept: 8
y-intercept: -4

Practice makes perfect

To determine the x- and y-intercepts of a line, we need to substitute 0 for one variable, solve, then repeat for the other variable.

Finding the x-intercept

Think of the point where the graph of an equation crosses the x-axis. The y-value of that ( x, y) coordinate pair is 0, and the x-value is the x-intercept. To find the x-intercept of the equation, we should substitute 0 for y and solve for x.
x-2y=8
x-2( 0)=8
x=8
An x-intercept of 8 means that the graph passes through the x-axis at the point ( 8,0).

Finding the y-intercept

Let's use the same concept to find the y-intercept. Consider the point where the graph of the equation crosses the y-axis. The x-value of the ( x, y) coordinate pair at the y-intercept is 0. Therefore, substituting 0 for x will give us the y-intercept.
x-2y=8
0-2y=8
-2y=8
y=-4
A y-intercept of -4 means that the graph passes through the y-axis at the point (0, -4).