` color{#e6f0ff}{@}color{#c7ddff}{Me}color{#99c2ff}{rr}color{#66a3ff}{yC}color{#3385ff}{hr}color{#0066ff}{is}color{#0044cc}{t}color{#002d80}{m}color{#001b4d}{as}color{#000a1a}{@} `

` a) ` ( Lỗi đề )

` b) 36 + x^2 - 12x `

` = x^2 - 12x + 36 `

` = x^2 - 2 * x * 6 + 6^2 `

` = ( x - 6 )^2 = ( 6 - x )^2 `

` c) 4x^2 - 12x + 9 `

` = ( 2x )^2 - 2 * 2x * 3 + 3^2 `

` = ( 2x - 3 )^2 `

` d) 1 - 10x + 25x^2 `

` = 1^2 - 2 * 1 * 5x + ( 5x )^2 `

` = ( 1 - 5x )^2 = ( 5x - 1 )^2 `

` e) ; f) ` ( Lỗi đề )