You will use the formula A=lw to find the area. Substitute 2x^3 in for the length and 4x^2 for the width. You would multiply both of these. 2×4 = 8, and x cubed times x squared equals X to the fifth power. You will add the exponents together because the exponent tells you how many times to multiply that value. If there are three x multiplied together (in x cubes) and two x multiplied together(in x squared) that makes five x multiplied together. The answer is represented as A=8x^5. ^ means to the power of.