Question

How do you factor 42r² -3rt - 9t²?

Answer 1

#42r^2 - 3rt - 9t^2 = 42r^2 - 21rt+ 18rt - 9t^2 = 21r( 2r - t) +9t( 2r-t) = (21r +9t)(2r-t) = 3(7r+3t)(2r-t)#