I'll do the first graph.
We can easily find the y intercept by inputting 0 for x.
y = -2(0) + 7
y = 7
The y-intercept is (0, 7)
To find the x intercept, isolate x.
y = -2x + 7
Add 2x to both sides.
2x + y = 7
Subtract y from both sides.
2x = -y + 7
Divide by 2 on both sides.
x = -1/2y + 3.5
Input 0 for y.
x = -1/2(0) + 3.5
x = 3.5
The x intercept is (3.5, 0)
Now try the rest own your own! :)