A spool of tungsten wire 290 m long and with a diameter of 0.440 mm is at 20.0°C. For tungsten, the resistivity is 5.60 ✕ 10−8 Ω · m and the temperature coefficient of resistivity is 4.50 ✕ 10−3 (°C)−1.

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

the higher the current the higher the mag field around it the higher the influence on the compass