4. Using sign-magnitude representation, evaluate the value of expressions given below (that use decimal numbers). Use 5 bits to represent a decimal number in sign-magnitude representation. Show your work for full credit. (6 points) a. (-2)+14 5. Using two's complement representation of numbers, perform the following operations and show the results. Use 5 bits for each number. (8 points) b. Subtract -15 from -7