Question

Phân tích đa thức sau thành nhân tử 

a) \(\left(x+5\right)^2-3\left(x+5\right)\)

b)\(2x\left(x-3\right)-\left(x-3\right)^2\)

c) \(x\left(x-7\right)+\left(7-x\right)^2\)

d)\(3x\left(x-9\right)^2-\left(9-x\right)^3\)

Các bạn giải giúp mik nhé !!!!

Cảm ơn các bạn nhìu <3 <3

Answer 1

\(\left(x+5\right)^2-3\left(x+5\right)\)

\(=\left(x+5\right)\left(x+5-3\right)\)

\(=\left(x+5\right)\left(x+2\right)\)

Answer 2

\(2x\left(x-3\right)-\left(x-3\right)^2\)

\(=\left(x-3\right)\left(2x-x+3\right)\)

\(=\left(x-3\right)\left(x+3\right)\)

Answer 3

\(x\left(x-7\right)+\left(7-x\right)^2\)

\(=\left(x-7\right)\left(x+x-7\right)\)

\(=\left(x-7\right)\left(2x-7\right)\)

Answer 4

\(3x\left(x-9\right)^2-\left(9-x\right)^3\)

\(\left(x-9\right)^2\left(3x-x+9\right)\)

\(\left(x-9\right)^2\left(2x+9\right)\)

Answer 5

d) \(3x\left(x-9\right)^2-\left(9-x\right)^3\)

\(=3x\left(x-9\right)^2-\left(9-x\right)^2\left(9-x\right)\)

\(=3x\left(x-9\right)^2+\left(x-9\right)^2\left(9-x\right)\)

\(=\left(x-9\right)^2\left(3x+9-x\right)\)

\(=\left(x-9\right)^2\left(2x+9\right)\)

Answer 6

Các câu còn lại giải như zZz Cool Kid zZz

Answer 7

a) \(\left(x+5\right)^2-3\left(x+5\right)\)

\(\Leftrightarrow x^2+2.5x+5^2-\left(3x+15\right)\)

\(\Leftrightarrow x^2+10x+25-3x-15\)

\(\Leftrightarrow x^2+7x+10\Leftrightarrow x^2+2x+5x+10\)

\(\Leftrightarrow x\left(x+2\right)+5\left(x+2\right)\Leftrightarrow\left(x+2\right)\left(x+5\right)\)

b)\(2x\left(x-3\right)-\left(x-3\right)^2\)

\(\Leftrightarrow2x^2-6x-\left(x^2-2.3x+9\right)\)

\(\Leftrightarrow2x^2-x^2-6x+6x-9\Leftrightarrow x^2-3^2\)

\(\Leftrightarrow\left(x-3\right)\left(x+3\right)\)

Answer 8

thay dấu\(\Leftrightarrow\)bằng dấu\(=\)nha bạn

Answer 9

a)(x+5)^2-3(x+5)=(x+5)(x+5-3)=(x+5)(x+2)

b)2x(x-3)-(x-3)^2=(x-3)(2x-x+3)=(x+3)(x-3)

Answer 10

c.\(x\left(x-7\right)+\left(7-x\right)^2\)

\(=x\left(x-7\right)-\left(x-7\right)^2\)

\(=\left[x-\left(x-7\right)\right]\left(x-7\right)\)