\(a.\frac{x}{4x^2y^3}và\frac{5}{6x^3y}\)
- MTC: 12x3y3
- NTP: 3x ; 2y2
\(\frac{x}{4x^2y^3}=\frac{x.3x}{4x^2y^3.3x}=\frac{3x^2}{12x^3y^3}\\ \frac{5}{6x^3y}=\frac{5.2y^2}{6x^3y.2y^2}=\frac{10y^2}{12x^3y^3}\)
\(b.\frac{2}{x^2+2xy}và\frac{1}{xy+2y^2}\)
- Ta có : x2 + 2xy = x ( x + 2y ) ; xy + 2y2 = y (x + 2y ).
-MTC : xy(x+2y)
- NTP : y ; x.
\(\frac{2}{x^2+2xy}=\frac{2.y}{y\left(x^2+2xy\right)}=\frac{2y}{x^2y+2xy^2}=\frac{2y}{xy\left(x+2y\right)}\\ \frac{1}{xy+2y^2}=\frac{1.x}{x\left(xy+2y^2\right)}=\frac{x}{x^2y+2xy^2}=\frac{x}{xy\left(x+2y\right)}\)
\(c.\frac{5}{6-2x}và\frac{3}{x^2-9};\frac{-5}{2x-6}và\frac{3}{x^2-9}\)
- Ta có : 2x - 6 = 2 ( x - 3 ) ; x2 - 9 = ( x + 3 ) ( x - 3 )
- MTC : 2 ( x - 3 ) ( x + 3 )
- NTP : x + 3 ; 2.
\(\frac{-5}{2x-6}=\frac{-5\left(x+3\right)}{\left(2x-6\right)\left(x+3\right)}=\frac{-5x-15}{2\left(x-3\right)\left(x+3\right)}\\ \frac{3}{x^2-9}=\frac{3.2}{2\left(x^2-9\right)}=\frac{6}{2\left(x-3\right)\left(x+3\right)}\)
Câu hỏi là gì thế bạn??????
Đề: Quy đồng mẫu thức hai phân thức