Đáp án+Giải thích các bước giải:
`1) (2x+1)^2 = (2x)^2 + 2.2x.1 + 1^2 = 4x^2 + 4x + 1`
`2) (x+3)^2 = x^2 + 2.x.3 + 3^2 = x^2 + 6x + 9`
`3) (a+5b)^2 = a^2 + 2.a.5b + (5b)^2 = a^2 + 10ab + 25b^2`
`4) (2a+5b)^2 = (2a)^2 + 2.2a.5b + (5b)^2 = 4a^2 + 20ab + 25b^2`
`5) (1/2x + 4)^2 = (1/2x)^2 + 2.1/2x.4 + 4^2 = 1/4x^2 + 4x + 16`
`6) (5-3x)^2 = 5^2 - 2.5.3x + (3x)^2 = 25 - 30x + 9x^2`
`7) (3x-1)^2 = (3x)^2 - 2.3x.1 + 1^2 = 9x^2 - 6x + 1`
`8) (4-3x)^2 = 4^2 - 2.4.3x + (3x)^2 = 16 - 24x + 9x^2`
`9) (2a-3b)^2 = (2a)^2 - 2.2a.3b + (3b)^2 = 4a^2 - 12ab + 9b^2`
`10) (2 - 1/2x)^2 = 2^2 - 2.2.1/2x + (1/2x)^2 = 4 - 2x + 1/4x^2`
