In cell E$20,$ enter a formula using the PPMT function to calculate the principal portion of loan payment $6.$ Enter a minus sign in front of the function name, and use cell D$7$ as the rate argument, entered as an absolute reference; cell A$20$ as the per argument; cell D$9$ as the nper argument, ontered as an absolute reference; and cell D$5$ as the pv argument, also entered as an absolute reference.