How do I delete a matching line and the previous one?

Question

I need delete a matching line and one previous to it. e.g In file below I need to remove lines 1 & 2.

I tried \"grep -v -B 1 \"page.of.\" 1.txt and I

Answer 1

grep -vf <(grep -B1 "page.*of" file | sed '/^--$/d') file