Fill in the boxes to complete the equality:

$11u-19u^2=u\left(\editable{}-\editable{}\right)$11u−19u2=u(−)

Factorise the following expression by taking out the highest common factor:

$42x-x^2$42x−x2

$4pqr-9pst$4pqr−9pst

Factorise the following expression:

$2yz-16xy+16xy^2z$2yz−16xy+16xy2z