a Since the y-variable is isolated, substitute it into the second equation.
B
b At what point do the lines intersect?
A
a (8, 12)
B
bGraph:
Comparison: We get the same solution.
Practice makes perfect
a Since the first equation already has an isolated y-variable, we can substitute the value it is equal to into the second equation. Then we can solve for x.
b The first equation does not have a slope which means it's a horizontal line. Additionally, since the equation is y=12 we know it's a horizontal line passing through (0,12).
To determine the second graph, we need two points. We can determine the first point by identifying the y-intercept of the equation. This requires us to rewrite the equation in slope-intercept form.
2x-y=4 ⇔ y=2x - 4
The y-intercept is (0, - 4). To find the second point, we can substitute an arbitrary value for x or y and solve for the corresponding x or y-coordinate. For example, we can find the x-intercept by substituting y=0 into the equation and solving for x.
