Houghton Mifflin Harcourt Algebra 1, 2015
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Houghton Mifflin Harcourt Algebra 1, 2015 View details
2. Using Intercepts
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Exercise 3 Page 177

Substitute 0 for each of the variables and then solve the equation for the other variable.

x-intercept: -3
y-intercept: 2

Practice makes perfect

To determine the x-intercept for the given equation, we will substitute 0 for y and solve for x. To determine the y-intercept, we will substitute 0 for x and solve for y.

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 equal to 0, and the x-value is the x-intercept. Consider the given equation. 2x-3y=-6Let's substitute 0 for y and solve for x.
2x-3y=-6
2x-3( 0)=-6
2x=-6
x=-3
The x-intercept of the equation is -3.

Finding the y-intercept

In the same way as above, now 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.
2x-3y=-6
2( 0)-3y=-6
-3y=-6
y=2
The y-intercept of the equation is 2.