Answer:
Green line: y = 5x + 2
Red line: y = 3x + 3
Purple line: y = 2x + 3
Step-by-step explanation:
1) All the given equations are in slope-intercept form, or [tex]y = mx + b[/tex] format. When an equation is written in this form, the constant on the right side of the equation, or the [tex]b[/tex], represents the y-intercept. The y-intercept is the point at which the line crosses the y-axis.
Knowing this, the y-intercept of [tex]y = 5x + 2[/tex] must be (0,2). The only graph in which the line crosses the y-axis at the point (0,2) is the one with the green line, thus the graph of [tex]y = 5x + 2[/tex] is the green one.
2) Now, since the other two equations share the same y-intercept, we have two graphs left. We can find out which graph belongs to which equation by taking a look at the slope of the line. The number in place of [tex]m[/tex], or the coefficient of the x-term in an equation in slope-intercept format represents the slope. Thus, the slope of [tex]y = 3x +3[/tex] is 3 and the slope of [tex]y = 2x + 3[/tex] is 2.
Now, find the slope of one of the lines in the graphs. To do so, use the slope formula, [tex]m = \frac{y_2-y_1}{x_2-x_1}[/tex]. Substitute the x and y values of two points on the chosen line into the formula in order to figure out the line's slope. I chose to find the slope of the red line, using the points (0,3) and (-1,0):
[tex]m = \frac{(0)-(3)}{(-1)-(0)} \\m = \frac{0-3}{-1-0}\\m = \frac{-3}{-1} \\m = 3[/tex]
So, the slope of the red line is 3. Its equation must be [tex]y = 3x + 3[/tex] since it has the matching slope. By process of elimination, the purple line must have the equation of [tex]y = 2x + 3[/tex].
