Question 86275
First, write the {{{x^2}}} - 7xy as {{{1/(x^2 - 7xy)}}}
Then, flip it and make it {{{(x^2 - 7xy)/1}}} and change the division to multiplication. Then, factor the {{{x^2}}} - 49{{{y^2}}}, the 6{{{x^2}}} + 42y and the {{{x^2}}} - 7xy. Cancel out all common factors, either vertically and/or diagonally, then multiply what's left straight across.