x²+(2a+b)xy+2aby²

=x²+2axy+bxy+2aby²

=(x²+bxy)+(2axy+2aby²)

=x(x+by)+2ay(x+by)

=(x+by)(x+2ay)

cảm ơn bn

\(8xy^3+x\left(x-y\right)^3\)

\(=x\left[8y^3+\left(x-y\right)^3\right]\)

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

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

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

\(=x\left(x+y\right)\left(7y^2+x^2-4xy\right)\)

a. \(9x^2+25-12xy+5y^2-10y\)

\(=\left(9x^2-12xy+4y^2\right)+\left(25+y^2-10y\right)\)

\(=9\left(x^2-\frac{4xy}{3}+\frac{4y^2}{9}\right)+\left(5-y\right)^2\)

\(=9\left(x-\frac{2y}{3}\right)^2+\left(5-y\right)^2\)

\(\frac{1}{2}.x+\frac{3}{5}.\left(x-2\right)=3\)

\(\frac{1}{2}x+\frac{3}{5}x-\frac{3}{5}.2=3\)

\(x\left(\frac{1}{2}+\frac{3}{5}\right)-\frac{6}{5}=3\)

\(x\frac{11}{10}-\frac{6}{5}=3\)

\(x.\frac{11}{10}=3+\frac{6}{5}=\frac{21}{5}\)

\(x=\frac{21}{5}\div\frac{11}{10}=\frac{42}{11}\)

\(\frac{1}{2}.x+\frac{3}{5}.\left(x-2\right)=3\)

\(\frac{1}{2}.x+\frac{3}{5}.x-2=3\)

\(\frac{1}{2}.x+\frac{3}{5}.x=3+2\)

\(\frac{1}{2}.x+\frac{3}{5}.x=5\)

\(x.\left(\frac{1}{2}+\frac{3}{5}\right)=5\)

\(x.\frac{11}{10}=5\)

\(x=5:\frac{11}{10}\)

\(x=\frac{50}{11}\)

vậy \(x=\frac{50}{11}\)

1. Viết các số dưới dạng hỗn sỗ

a) 3m 11cm =..3,11.....m                                     b) 2kg 21g =....2,021.........kg

c) 5dam 47dm =........54,7...m                             d) 5m²  43dm² =....5,43......m²

a/ 3m 11cm= 3,11m                                       b/2kg 21g= 2,021kg

c/5dam 47dm= 54,7m                                   d/5m* 43dm*= 5,43m*

\(\left(x+\frac{1}{5}\right)^2=\frac{26}{25}-\frac{17}{25}\)

\(\left(x+\frac{1}{5}\right)^2=\frac{9}{25}\)

\(\left(x+\frac{1}{5}\right)^2=\left(\frac{3}{5}\right)^2\)

\(x+\frac{1}{5}=\frac{3}{5}\)

\(x=\frac{3}{5}-\frac{1}{5}\)

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

vậy \(x=\frac{2}{5}\)

\(\left(x+\frac{1}{5}\right)^2+\frac{17}{25}=\frac{26}{25}\)

\(\left(x+\frac{1}{5}\right)^2=\frac{26}{25}-\frac{17}{25}\)

\(\left(x+\frac{1}{5}\right)^2=\frac{9}{25}\)

\(\left(x+\frac{1}{5}\right)^2=\left(\frac{3}{5}\right)^2\)

\(x+\frac{1}{5}=\frac{3}{5}\)

\(x=\frac{3}{5}-\frac{1}{5}\)

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