Simplify the following expression. (r - 9) (r -9)

Answer:
r^2-18r+81
Step-by-step explanation:
rxr=r^2
rx-9=-9r
-9xr=-9r
-9x-9=81
-9r-9r=-18r
Answer:
r^2-18r+81
Step-by-step explanation:
r × r = r^2
r × -9 = -9r
-9 × r = -9r
-9 × -9 = 81
->
r^2-18r+81
Hope that helps! :)