EXPLANATION
Given the expression:
[tex]192x^2y+72x^3-24\text{rxy-}9rx^2[/tex]
Grouping like terms and taking x as a common factor:
[tex]3x(64x^{}y+24x^2-8ry-3rx)[/tex]
Factor 64xy + 24x^2 - 8ry - 3rx:
[tex]=(64xy\text{ + 24x\textasciicircum{}2)- (8ry + 3rx)}[/tex]
