Question

Help checking my answers? WILL GIVE MEDAL

Answer 1

for (a): I need to figure out how to get -1.22 positive without being a fraction

Answer 2

@tester97

Answer 3

@agent0smith

Answer 4

Wouldn't it just simply go down $1.22

Answer 5

haha yeah....

Answer 6

Pick a value of x: let's say 10. y = -1.22x +96.20 = -12.20 + 96.20 = 84
now do the same with x+1 = 11: y = -1.22(11)+96.20 = -13.42 + 96.20 = 82.78
82.78 - 84 = -$1.22 so it decreased by $1.22, just as we would expect.

Answer 7

f(x+1) = -1.22(x + 1) + 96.20
= -1.22x -1.22 +96.20
=-1.22x + 94.98

Answer 8

Yes, that is a better way to look at it @whpalmer4

Answer 9

not sure it's a better way, just an illustrated way :-)

we have \[f(x) = -1.22x + 96.20\]
\[f(x+1) = -1.22(x+1) + 96.20\]
\[f(x+1)-f(x) = -1.22(x+1)+96.20-(-1.22x+96.20)\]\[=-1.22(x+1) +96.20 +1.22x-96.20\]\[=-1.22(x+1)+1.22(x) = -1.22x -1.22 + 1.22x = -1.22\]

Our function is just a line in slope-intercept form: \(y = mx+b\) if we move one point along the x axis (to the right), the value changes by 1*m.

Answer 10

Our slope is -$1.22/degree, if you put units on it. Increase the temperature by 10 degrees, and the cost goes down by -$1.22/degree * 10 degrees = -$12.22

Decrease the temperature by 20 degrees, the cost goes up by -$1.22/degree * -20 degrees = $24.44

Answer 11

Thank you SO much. Could one of you guys help me with a graph?

Answer 12

Yep :) I tagged you already..