Question

(2/3×-3/4y)2

(3m+n).(3m-n)

Answer 1

$( \frac{2x}{3} - \frac{3y}{4} )^2= \\ \\ ( \frac{2x}{3} )^2-2.( \frac{2x}{3} )( \frac{3y}{4})+( \frac{3y}{4} )^2= \\ \\ \frac{4x^2}{9} - \frac{\not12xy}{\not12} + \frac{9y^2}{16} = \\ \\ \frac{4x^2}{9} -xy+ \frac{9y^2}{16} \\ \\ --------- \\ (3m+n)(3m-n)= \\ \\ (3m)^2-n^2= \\ \\ 9m^2-n^2$