`a) (2x-3)^2 = (2x)^2 - 2. 2x . 3 + 3^2 = 4x^2 - 12x + 9`
`b) (5/2 - x)^2 = (5/2)^2 - 2 . 5/2 . x + x^2 = 25/4 - 5x + x^2`
`c) (2x+3y)^2 = (2x)^2 + 2 . 2x . 3y + (3y)^2 = 4x^2 + 12xy + 9y^2`
`d) (3x + 2/3yz)^2 = (3x)^2 + 2 . 3x . 2/3 yz + (2/3yz)^2 = 9x^2 + 4xyz + 4/9y^2z^2`