That picture tho fiejfjejdjwjdhehfhueuxhrhfjsjdjrjr :)
From the attached graphic:
e = c*h/wavelength therefore,
wavelength = c*h / e
wavelength = 299,792,458 * 6.62606957e-34 / 3.38x10^-19
wavelength = 5.8771e-7 meters
Answer:
so
slope is calculated this way:

let's calculate y init by:
3 = -3×2 + b
b = 9
so equation is:
y=-3x+9