Question

A) 27x².(y-1)-9x³.(1-y)

b)8x³ + 1/27

c)49.(y-4)²-9.(y+2)² 

^{phân tích đa thức thành nhân tử nhé}

Answer 1

a)27x².(y-1)9x³.(1-y)

=27x².(y-1)+9x³.(y-1)

=9x²(y-1)[3+x]

b)8x³ + 1/27

=(2x)³ + (\(\frac{1}{3}\))³

= (2x+\(\frac{1}{3}\))(\(\left(2x\right)^2-\frac{2}{3}x+\left(\frac{1}{3}\right)^2\)

= (2x+\(\frac{1}{3}\))(\(\left(2x\right)^2-\frac{2}{3}x+\left(\frac{1}{3}\right)^2\)

c)49.(y-4)²-9.(y+2)²=[7(y-4)]²-[3(y+2)]²=[7(y-4)+3(y+2)][7(y-4)-3(y+2)]=(7y-28+3y+6)(7y-28-3y-6)=(10y-22)(4y-34)

 

Answer 2

a) 27x² ( y - 1) - 9x³ ( 1 - y)

=27x² (y-1) + 9x³ ( y - 1 )

= (27x² + 9x³) ( y -1 )

=9x² ( x + 3) ( y - 1)

b)8x³+1/27

\(=\left(2x\right)^3+\left(\frac{1}{3}\right)^3\)

\(=\left(\frac{2x}{9}+\frac{1}{27}\right)\left(36x^2-6x+1\right)\)

c)49 ( y - 4 )² - 9 ( y + 2)² 

= [7(y - 4)]² - [3(y + 2)]²

= (7y - 28 + 3y + 6)(7y - 28 - 3y - 6)

= (10y - 22)(4y - 34)

= 4(5y - 11)(2y - 34)