Giải thích các bước giải:
Bài 1:
$a, (2+√3)^2=4+4√3+3=7+4√3$
$b, (2√3-5)^2=12-20√3+25=37-20√3$
$c, 3√3+x^3=(√3)^3+x^3=(√3+x)(3-√3.x+x^2)$
$d, (√x-5)^2=x-10√x+25$
$e, (√3+√7)^2=3+2.√21+7=10+2.√21$
Bài 2:
$a, (3√3+5)(8√3-4)=72-12√3+40√3-20=52+28√3$
$b, (5√x+2)(4√x-1)=20x-5√x+8√x-2=20x+3√x-2$
$c, (2√7+4)(2√7-4)=(2√7)^2-4^2=28-16=12$
$d, (3x-5y+2)(4x-2y)=[(4x+2y)-(x+7y)+2)(4x-2y)=16x^2-4y^2-(x+7y)(4x-2y)+2(4x-2y)$
$=16x^2-4y^2-4x^2+2xy-28xy+14y^2+8x-4y=12x^2+10y^2-26xy+8x-4y$
