An infinite sheet of charge, oriented perpendicular to the x-axis, passes through

An infinite sheet of charge, oriented perpendicular to the x-axis, passes through x = 0. It has a surface charge density σ1 = -3 μC/m^2. A thick, infinite conducting slab, also oriented perpendicular to the x-axis, occupies the region between a = 2.1 cm and b = 4.6 cm. The conducting slab has a net charge per unit area of σ2 = 78 μC/m^2. (Recall that the surface charge densities σa and σb on the slab surfaces at a and b, respectively, sum to equal the net charge per unit area: σa + σb = σ2.)

a. What is Ex(P), the value of the x-component of the electric field at point P, located a distance 7.2 cm from the infinite sheet of charge?
b. What is Ey(P), the value of the y-component of the electric field at point P, located a distance 7.2 cm from the infinite sheet of charge?
c. What is Ex(R), the value of the x-component of the electric field at point R, located a distance 1.05 cm from the infinite sheet of charge?
d. What is Ey(R), the value of the y-component of the electric field at point R, located a distance 1.05 cm from the infinite sheet of charge?
e. What is σb, the charge per unit area on thesurface of the slab located at x = 4.9 cm?
f. What is Ex, the value of the x-component of the electric field at a point on the x-axis located at x = 3.22 cm ?
g. What is σa, the charge per unit area on the surface of the slab located at x = 2.1 cm?
h. Where along the x-axis is the magnitude of the electric field equal to zero?