Answer: D
Step-by-step explanation: 
Start with y=mx+b
B is your y intercept
m is your slope
The points you have are (-1,4) and (1,-2)
To find the slow you Do Y2-Y1/X2-X1
(-2-4)/ (-1-1)
-6/-2
your m is 3
Now you go back to the equation of a Line y=mx+b
to find b (your y intercept) take on of the two points, and substitute it's y value in the equation Let's take (1,-2)
Y=mx+b
-2=3(1)+b
-2=3+b
b=-5
you now know that
b=-5
m=3x
The equation is
y=3x-5
An = a1 + (n-1)*d
n = term to find = 30
a1 = first term = 20
d = common difference = 2
a30 = 20 + (30 - 1) * 2
a30 = 20 + 29 * 2
a30 = 20 + 58
a30 = 78
sn = (n (a1 + a30)) / 2
s30 = (30(20 + 78) / 2
s30 = (30(98) / 2
s30 = 2940/2
s30 = 1470 <===
You can multiply 2x7 to get 14