Question

phân tích các đa thức sau thành nhân tử

a, x² +6x+9 b, 10x-25-x²

c,8x³-1/8 c, 1/25x²-64y²

Answer 1

a) x² + 6x + 9 = x² + 2.3.x + 3² = (x + 3)²

b) 10x - 25 - x² = - (x² - 2.5.x + 5²) = - (x - 5)²

c) \(8x^3-\dfrac{1}{8}=\left(2x\right)^3-\left(\dfrac{1}{2}\right)^3=\left(2x-\dfrac{1}{2}\right)\left(4x^2+x+\dfrac{1}{4}\right)\)

d) 25x² - 64y² = (5x)² - (8y)² = (5x - 8y)(5x + 8y)

Answer 2

\(a,x^2+6x+9=\left(x+3\right)^2\)

Answer 3

\(b,10x-25-x^2=-\left(x^2-10x+25\right)=-\left(x-5\right)^2\)

Answer 4

a. = ( x+3)^2

b. = - (x^2 - 2x5 + 5^2) = - (x - 5)^2

c. 8x^3 - 1/8 = (2x)^3 - (1/2)^3 = (2x - 1/2)(4x^2 + x + 1/4)

d.1/25x^2 - 64y^2 = (1/5x)^2 - (8y)^2

= (1/5x - 8y)(1/5x + 8y)

Answer 5

c, \(8x^3-\dfrac{1}{8}=\left(2x\right)^3-\left(\dfrac{1}{2}\right)^3=\left(2x-\dfrac{1}{2}\right)\left(4x^2+x+\dfrac{1}{4}\right)\)

Answer 6

\(d,\dfrac{1}{25}x^2-64y^2=\left(\dfrac{1}{5}x\right)^2-\left(8y\right)^2=\left(\dfrac{1}{5}x+8y\right)\left(\dfrac{1}{5}x-8y\right)\)

Answer 7

a. (x+3)2

b. (x-5)²

c. (2x-1/2)(4x^2​+x+1/4)

d. (1/5+8)(1/5-8)

Khỏi cảm ơn :)))