mình chỉ phân tích thôi

a) 6x(4-x)+x-4

=6x(4-x)-(4-x)

=(6x-1)(4-x)

c) 25x^2-10x+1-16z^2

=(5x-1)^2-16z^2

=(5x-1-4z)(5x-1+4z)

ban xem lại đề bài câu b đi chắc là sai đó

còn các câu trên bạn tự làm nhé

Thực hiện phép tính:

a) (2x-3y)(4x²+6xy+9y²)

=8x³-27y³

b) (6x³+3x²+4x+2):(3x²+2)

=(3x²+2)(2x+1):(3x²+2)

=2x+1

c) (x+2)²+(3-x)-2(x+3)(x-3)

=x²+4x+4+3-x-2x²+18

=-x²+4x+25

Bài 2: 

a: 6x(4-x)+(x-4)

=6x(4-x)-(4-x)

=(4-x)(6x-1)

b: \(=x^2-1+y\left(x^2-1\right)\)

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

c: \(=\left(5x-1\right)^2-\left(4z\right)^2\)

=(5x-1-4z)(5x-1+4z)

\(\frac{4}{x+2}+\frac{3}{x-2}+\frac{-5x-2}{x^2-4}\)ĐK : \(x\ne\pm2\)

\(=\frac{4\left(x-2\right)+3\left(x+2\right)-5x-2}{\left(x+2\right)\left(x-2\right)}=\frac{4x-8+3x+6-5x-2}{\left(x+2\right)\left(x-2\right)}\)

\(=\frac{2x-4}{\left(x+2\right)\left(x-2\right)}=\frac{2\left(x-2\right)}{\left(x+2\right)\left(x-2\right)}=\frac{2}{x+2}\)

\(a,\dfrac{x+1}{5}-\dfrac{2}{x}\)

\(=\dfrac{x\left(x+1\right)-2.5}{5x}=\dfrac{x^2+x-10}{5x}\)

\(b,\dfrac{x+y}{9x}:\dfrac{x+y}{3x}\)

\(=\dfrac{x+y}{9x}.\dfrac{3x}{x+y}=\dfrac{1}{3}\)

a. \(\dfrac{x+1}{5}\)-\(\dfrac{2}{x}\)=\(\dfrac{x\left(x+1\right)-2.5}{5x}\)=\(\dfrac{x^2+x-10}{5x}\)

b. \(\dfrac{x+y}{9x}:\dfrac{x+y}{3x}\)=\(\dfrac{x+y}{9x}.\dfrac{3x}{x+y}=\dfrac{1}{3}\)

\(\frac{\left(x-3\right)^3}{3x^2}:\frac{x^2-6x+9}{6x}\)

\(=\frac{\left(x-3\right)^3}{3x^2}.\frac{6x}{\left(x-3\right)^2}\)

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

\(=\frac{2x-6}{x}\)

#H

Trả lời:

\(\frac{\left(x-3\right)^3}{3x^2}:\frac{x^2-6x+9}{6x}\)

\(=\frac{\left(x-3\right)^3}{3x^2}.\frac{6x}{x^2-6x+9}\)

\(=\frac{\left(x-3\right)^3}{3x^2}.\frac{6x}{\left(x-3\right)^2}\)

\(=\frac{\left(x-3\right)^3.6x}{3x^2.\left(x-3\right)^2}\)

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

\(\left(\dfrac{x-2}{x+2}+\dfrac{6x-4}{x^2-4}\right):\dfrac{x+1}{x-2}\)

\(=\dfrac{x^2-4x+4+6x-4}{\left(x+2\right)\left(x-2\right)}\cdot\dfrac{x-2}{x+1}\)

\(=\dfrac{x^2+2x}{x+2}\cdot\dfrac{1}{x+1}=\dfrac{x}{x+1}\)

Em ko biết làm

3/5 + 2/7-1/3 trả lời giúp tôi .Nhanh  nhé

Sao toàn viết chữ thế ? Đọc sao nổi ? Viết lại ra số đi

\(a.\frac{2}{3}+\frac{1}{5}\cdot\frac{10}{7}\)

\(=\frac{2}{3}+\frac{1\cdot2}{1\cdot7}\)

\(=\frac{2}{3}+\frac{2}{7}=\frac{2\cdot7}{21}+\frac{2\cdot3}{21}=\frac{14}{21}+\frac{6}{21}=\frac{20}{21}\)

\(b.\frac{2}{7}\cdot\frac{4}{7}+\frac{2}{7}\cdot\frac{3}{7}\)

\(=\frac{2}{7}\cdot\left(\frac{4}{7}+\frac{3}{7}\right)\)

\(=\frac{2}{7}\cdot\frac{7}{7}=\frac{2}{7}\cdot1=\frac{2}{7}\)

\(c.\left[-\frac{1}{4}+\frac{3}{10}\right]:\left(-\frac{3}{5}\right)-\frac{7}{6}\)

\(=\left[-\frac{5}{20}+\frac{6}{20}\right]:\left(-\frac{3}{5}\right)-\frac{7}{6}\)

\(=\frac{1}{20}:\left(-\frac{3}{5}\right)-\frac{7}{6}\)

\(=\frac{1}{20}\cdot\left(-\frac{5}{3}\right)-\frac{7}{6}\)

\(=\frac{1\cdot\left(-1\right)}{4\cdot3}-\frac{7}{6}\)

\(=\left(-\frac{1}{12}\right)-\frac{7}{6}=\left(-\frac{1}{12}\right)-\frac{14}{12}=-\frac{15}{12}\)

bài 2 :a) \(2x-2\frac{2}{7}=2\frac{5}{7}\)

\(2x=2\frac{5}{7}-2\frac{2}{7}\)

\(2x=\left(2-2\right)+\left(\frac{5}{7}-\frac{2}{7}\right)\)

\(2x=0+\frac{3}{7}\)

\(2x=\frac{3}{7}\)

\(x=\frac{3}{7}:2=\frac{3}{7}\cdot\frac{1}{2}=\frac{3}{14}\)

\(b.\frac{17}{13x}=\frac{4}{39}\)

\(\Rightarrow13x\cdot4=17\cdot39\)

\(\Rightarrow13x\cdot4=663\)

\(\Rightarrow13x=663:4\)

\(\Rightarrow13x=165,75\)

\(\Rightarrow x=165,75:13\)

\(\Rightarrow x=12,75\)

\(****nha!!!!!!!!!!!!\)

dung may inh la tinh ra