Y=mx+b
y=2x+b
then substitute x and y
3=2(3) + b
3= 6 + b
b=-3
y=2x-3
Answer:
A. 
B. The y intercept is 4.8
Step-by-step explanation:
Given

Solving (a): Write as a function.
To do this, we simply substitute f(n) for 
becomes

Open Bracket

Collect Like Terms


B. The y intercept.
To get the y intercept, we set n to 0
i.e



Hence, the y intercept is 4.8
......................... 1/2
P(5,2) = n! /(n-r)!
n = 5, r = 2:
= (5 x 4 x 3 x 2 x 1 ) / 3 x 2 x 1
Cancel out common factors:
= 5 x 4 = 20
The answer is 20.