Answer:
Both, you and your friend, are correct.
Step-by-step explanation:
5 P 5 = 5!
A shortcut I learned is that in the permutation equation nPn when n is the same on both sides, it is equal to if you used factorial, n!.
Answer:
0
Step-by-step explanation:
x2 +4x-21=0. solve for x


8m^2+18m+9=0
Multiply 2m by 4m to get 8m^2. Multiply 2m by 3 to get 6m. Multiply 3 by 4m to get 12m. Add the 6m and 12m to make 18m. Multiply 3 by 3 to get the integer 9. Set it all equal to 0.