`a, (3x+1)^2 = 9x^2 + 6x + 1`.
`b, (4x+5y)^2 = 16x^2 + 20xy + 25y^2`
`c, (5x-1/2)^2 = 25x^2 - 5x + 1/4`
`d, (-x+2y^2)^2 = x^2 - 2y^2x + 4y^4`.
`a)`
`(3x + 1)^2`
`= 9x^2 + 6x + 1`
`b)`
`(4x + 5y)^2`
`= 16x^2 + 40xy + 25y^2`
`c)`
`(5x - 1/2)^2`
`= 25x^2 - 5x + 1/4`
`d)`
`(-x + 2y^2)^2`
`= x^2 - 4xy^2 + 4y^4`