It's a linear graph, so we can use the slope-intercept form. Let's find the y-intercept first, which happens ar y = -3. Now let's find the slope. To do so, let's pick two points on the graph (relatively easy ones): (0, -3) and (5, -7).
Let's find the slope:

Let's write it in slope-intercept form. Recall that slope-intercept form is:

Where m = slope and b = y-intercept. We have all the parts, so let's write it:
Answer:22.5
Step-by-step explanation:
The original price of the shirt would be $30
1.20 could be a possibility...
Answer:
x = 1, y = 4
Step-by-step explanation:
This is very simple
Since you have 2 equations with the same coefficient of x, just minus one equation from another:
x + 3y = 13
-
x + 2y = 9
1y = 4
Sub y = 4 into any of the 2 equation,
x + 3(4) = 13
x + 12 = 13
x = 13 - 12
= 1