Answer:
y = 9x
Step-by-step explanation:
You can set up linear equations like this: y = mx + b, where m is the slope or rate, and b is the y-intercept.
9 would be the slope, since he has to pay $9 per gift.
The y-intercept is when x = 0, but if he doesn't buy any gifts, he won't have to pay anything, so b = 0. You don't have to include it since it's 0.
So, it's just y = 9x
Hope that helps! :D
Answer:
y = 4x+23
Step-by-step explanation:
The slope intercept form of a line is
y = mx+b where m is the slope and b is the y intercept
y = 4x+b
Substitute the point into the equation
7 = 4(-4)+b
7 = -16+b
Add 16 to each side
7+16 = b
23 = b
y = 4x+23
