Apotential difference of 12v produces a current of 0.30a in a piece of cooper wire. what is the resistance of the copper wire?

Well , its a easy problem  

By ohms law,  

we have V= IR  

Where V is the voltage applied across the wire and R is the resistance and I is the current  

=> R = V/I  

=> R = 12/0.3 = 40 ohm

because it says use -2,0,and 2 for x, we can plug those numbers into the equation. y/4=3/4(-2)+2   y/4= -1 1/2 +2 now to get x by itself, we can multiply each side by 4. y=-6+8 which equals y=2 when x=-2. now you can do the same thing with 0 and 2 as x. you get y=8 when x=0 and y=14 when x=2.

x   |   y

-2 |   2

0   |   8

2   |   14