..........................

a)\(a^4+a^3+a^3b+a^2b=\left(a^4+a^3b\right)+\left(a^3+a^2b\right)\)

\(=a^3\left(a+b\right)+a^2\left(a+b\right)\)

\(=\left(a^3+a^2\right)\left(a+b\right)\)

\(=a^2\left(a+1\right)\left(a+b\right)\)

b)\(\left(x-y+4\right)^2-\left(2x+3y-1\right)^2\)

\(=\left[\left(x-y+4\right)-\left(2x+3y-1\right)\right]\left[\left(x-y+4\right)+\left(2x+3y-1\right)\right]\)

\(=\left(x-y+4-2x-3y+1\right)\left(x-y+4+2x+3y-1\right)\)

\(=\left(-x-4y+5\right)\left(4x+2y+3\right)\)

c)\(x^2\left(y-z\right)+y^2\left(z-x\right)+z^2\left(x-y\right)\)

\(=x^2\left(y-z\right)+y^2\left(z-y+y-x\right)+z^2\left(x-y\right)\)

\(=x^2\left(y-z\right)-y^2\left(y-z\right)-y^2\left(x-y\right)+z^2\left(x-y\right)\)

\(=\left(y-z\right)\left(x^2-y^2\right)-\left(x-y\right)\left(y^2-z^2\right)\)

\(=\left(y-z\right)\left(x-y\right)\left(x+y\right)-\left(x-y\right)\left(y-z\right)\left(y+z\right)\)

\(=\left(y-z\right)\left(x-y\right)\left(x+y-y-z\right)\)

\(=\left(y-z\right)\left(x-y\right)\left(x-z\right)\)

g: \(3\left(x-y\right)-5x\left(y-x\right)=\left(x-y\right)\left(5x+3\right)\)

f: \(4x^2\left(x+1\right)+2x^2\left(x+1\right)\)

\(=6x^2\left(x+1\right)\)

f: \(4x^2\left(x+1\right)+2x^2\left(x+1\right)=6x^2\left(x+1\right)\)

g: \(3\left(x-y\right)-5x\left(y-x\right)=\left(x-y\right)\left(5x+3\right)\)

câu f có ( x+1) là nhân tử chung

câu g đổi dấu - thành + thì (y-x) sẽ thành (x-y)

e: \(8\left(x+3y\right)-16x\left(x+3y\right)=8\left(x+3y\right)\left(1-2x\right)\)

f: \(4x^2\left(x+1\right)+2x^2\left(x+1\right)=6x^2\left(x+1\right)\)

a: \(9x^3y^2+3x^2y^2\)

\(=3x^2y^2\cdot3x+3x^2y^2\cdot1\)

\(=3x^2y^2\left(3x+1\right)\)

b: \(x^2-2x+1-y^2\)

\(=\left(x^2-2x+1\right)-y^2\)

\(=\left(x-1\right)^2-y^2\)

\(=\left(x-1-y\right)\left(x-1+y\right)\)

a) 1/2(x³+8)=1/2(x+2)(x²-2x+4)

b) x⁴(x-y)+2x³(x-y)=x³(x+2)(x-y)

c) x²-(y²-6y+9)=x²-(y-3)²=(x-y+3)(x+y-3)

d) xy(x³+y³)=xy(x+y)(x²-xy+y²)

e)3x²(x²-25y²)=3x²(x-5y)(x+5y)

f) 4x⁴+4x²y²+y⁴-4x²y²= (2x²+y²)²-(2xy)²=(2x²-2xy+y²)(2x²+2xy+y²)

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

b) \(x^5-x^4y+2x^4-2x^3y=x^3\left(x^2-xy+2x-2y\right)=x^3\left[x\left(x-y\right)+2\left(x-y\right)\right]=x^2\left(x-y\right)\left(x+2\right)\)

c) \(x^2-y^2+6y-9=x^2-\left(y-3\right)^2=\left(x+y-3\right)\left(x-y+3\right)\)

d) \(x^4y+xy^4=xy\left(x^3+y^3\right)=xy\left(x+y\right)\left(x^2-xy+y^2\right)\)

e) \(3x^4-75x^2y^2=3x^2\left(x^2-25y^2\right)=3x^2\left(x+5y\right)\left(x-5y\right)\).

f) \(4x^4+y^4=\left(2x^2+y^2\right)^2-\left(2xy\right)^2=\left(2x^2+y^2+2xy\right)\left(2x^2-y^2-2xy\right)\)

dễ mà 2/5 =6/7 em ak =)

cảm ơn nha

Câu hỏi của TRẦN THỊ BÍCH HỒNG - Toán lớp 7 - Học toán với OnlineMath

a) \(4x^2-4x+1=\left(2x-1\right)^2\)

\(3x\left(x-5\right)-x\left(4+3x\right)=43\)

\(\Leftrightarrow3x^2-15x-4x-3x^2=43\)

\(\Leftrightarrow-19x=43\)

\(\Leftrightarrow x=\frac{-43}{19}\)

b) 64x³ + 48x²y + 12xy² + y³

^{\(=\left(4x\right)^3+3.4^2.x^2y+3.4xy^2+y^3\)}

^{\(=\left(4x+y\right)^3\)}

a) \(x^2+2xy^3-3z+4xy-5xy^2+2xy-5z\)

\(=x^2+2xy^3-5xy^2-\left(3z+5z\right)+\left(4xy+2xy\right)\)

\(=x^2+2xy^3-5xy^2-8z+6xy\)

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

\(=\left(x-3y\right)\left[x^2-x\cdot3y+\left(3y\right)^2\right]\)

\(=x^3-\left(3y\right)^3\)

\(=x^3-27y^3\)

c) \(\left(2x-y\right)\left(2x+y\right)\)

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

\(=4x^2-y^2\)

d) \(\left(3x-y\right)\left(2y+5\right)-16x4y\)

\(=6xy+15x-2y^2-5y-64xy\)

\(=-58xy+15x-2y^2-5y\)

Bạn xem lại đề bài nhé!