I would be really grateful explain or help me with questions 8 and 9 i’ve never been good at math

Slope intercept form: y=mx+b
slope: m
y-intercept: b

8. slope= 3
x= -7
y = -8
plug these values in to slope intercept form find the y-intercept:
-8 = -7(3) + b
-8 = -21 + b
-8 + 21 = b
b = 13
now plug the slope and y- intercept values into slope intercept form:
y = 3x + 13 (final answer)

9. x1= -8 x2= 14
y1= -14. y2= -14
to calculate slope: y2-y1/ x2-x1
plug in x and y values
m= -14 - (-14)/ 14- (-8) = 0/22= 0
m= 0
find y-intercept by plugging in values
-14 = -8(0) + b
b= -14
plug slope and y- intercept into slope intercept form
y = x - 14 (final answer)

The answer is that the rate of change is $50 per 1 monthhope this ; )