Đáp án:
Giải thích các bước giải:
a, 4x² +4x+1=(2x)²+2.2x+1=(2x+1)²
(A+B)² =A²+2AB+B²
b, 1+12x+36x² =1+2.6x+6²=(1+6x)²
(A+B)² =A²+2AB+B²
c, 9x²-24xy+16y² =(3x)²-2.3x.4y +(4y)²=(3x-4y)²
(A+B)² =A²+2AB+B²
e, (5x-4)²-49x² =(5x-4-7x)(5x-4+7x)
=(-4-3x)(12x-4)
A²-B²=(A-B)(A+B)
g, (2x+5)²-(x-9)² = (2x+5-x+9)(2x+5+x-9)=(x+14)(3x-7)
A²-B²=(A-B)(A+B)
h, 9(2x+3y)²-4(x+1)² =(6x+9y -2x-2)(6x+9y+2x+2) = (4x+9y-2)(8x+9y+2)
A²-B²=(A-B)(A+B)
i, 4b²c²- (b²+c²-a²)²=(2bc)² -(b²+c²-a²)²=(2bc-b²-c²+a²)(2bc +b²+c²-a²)
k, 1+8x^6 .y^3 =1+(2x²y)³=(2x²y+1)(4x^4.y²-2x²y+1)
A³+B³=(A+B)(A²-AB+B²)
l, 27x³+y³/8 =(3x)³+(y/2)³=(3x+y/2)(9x² -3xy/8 +y²/4)
A³+B³=(A+B)(A²-AB+B²)
m, 125x³+27y³=(5x)³+(3y)³=(5x+3y)(25x²-15xy+9y²)
A³+B³=(A+B)(A²-AB+B²)
