ANSWER

EXPLANATION
The point-slope equation of a straight line is given by:

Where m is the slope.
The line goes through (-5,4) and (1,6).
The slope of this line is,


The point-slope equation is

Set it up with variables; tomatoes=t, sunflowers=s, corn=c
320=t+s+c
This year;
t=2s
c=t+40
so, replace 2s for t; c=2s+40
now we can put those factors in for 320=t+c+s
320= 2s+2s+40+s
(SIMPLIFY)---> 320=5s+40----> 5s+280----> s=56
now incorporate the s value into the other equations.
c=2s+40----> c=56(2)=40 ----> c=152
t=2s -----> t=2(56) ----> t=112
TOMATOES= 112 acres
CORN= 152 acres
SUNFLOWERS= 56 acres
To check your work: 320=t+s+c ----> 320=112+156+56
Answer: ($3.90)(12) - (2)($3.90) = 39.00
39.00/12 = 3.25 per pretzel
The common difference is basically the second number minus the first (or the 3rd-2nd, and so on). The answer should be B.