(3x^2 - 12y^2) / (x^2 + 4xy + 4y^2),
3(x^2 - 4y^2) / (x + 2y) (x + 2y),
3(x + 2y) (x - 2y) / (x + 2y)(x - 2y),
Cancel two (x + 2y) factors and get:
3(x - 2y) / (x + 2y).
Reduce each rational expression to lowest terms:
3x^2-12y^2 over x^2+4xy+4y^2
2 answers
CORRECTION: The denominator of the 3rd expression should be (x + 2y) (x + 2y).