A solid conducting sphere of radius 2.00 cm has a charge of 8x10^-6 C. A conducting spherical shell of inner radius 4.00 cm and outer radius 5.00 cm is concentric with the solid sphere and has a total charge of -4x10^-6 C. Find the electric field at (a) r = 1.00 cm, (b) r = 3.00 cm, (c) r = 4.50 cm, and (d) r = 7.00cm from the center of this charge configuration.