Which of the following are factors of $33yw$33yw? Select all that apply.
$11$11
$66wy$66wy
$yw$yw
$3w$3w
$yw^2$yw2
$33$33
What is the highest common factor of $3$3 and $15x$15x?
What is the highest common factor of $6x$6x and $21$21?
What term must go in the space to complete the statement?