`a) (2x+3y)^2`
`=(2x)^2 + 2.2x.3y + (3y)^2`
`=4x^2 +12xy + 9y^2`
`b) (5x-y)^2`
`=(5x)^2 +2.5x.y +y^2`
`=25x^2 +10xy +y^2`
`c) (2x+y^2)^3`
`=(2x)^3 +3.(2x)^2 .y^2+3.2x.(y^2)^2 +(y^2)^3`
`=8x^3+3.4x^2 .y^2+3.2x.y^4 +y^6`
`=8x^3 +12x^2y^2+6xy^4 +y^6`
`d) (x+1/4)^2`
`=x^2+2.1/4 .x +(1/4)^2`
`=x^2+\frac{1}{2}x+1/16`
`e) (\frac{2}{3}x^2-\frac{1}{2}y)^3`
`=(\frac{2}{3}x^2)^3-3.(\frac{2}{3}x^2)^2 .\frac{1}{2}y+3.\frac{2}{3}x^2 .(\frac{1}{2}y)^2 - (\frac{1}{2}y)^3`
`=\frac{8}{27}x^6-\frac{2}{3}x^4y+\frac{1}{2}x^2y-\frac{1}{8}y`