Question

[♥ℒêღɦℴàทջღℒℴทջ︵²ᵏ⁸ ( ℱℐℛℰℳᎾUЅℰ )]

giúp mik vs nhé bài 4, 7 ,10 nha :3

thanks

Answer 1

[Darlingg🥝]

4) \(\frac{7x}{x-2}+\frac{14}{2-x}=\frac{7x}{x-2}-\frac{14}{x-2}=\frac{7x-14}{x-2}=\frac{7\left(x-2\right)}{x-2}=7\)

7) \(\frac{1}{x^2-1}+\frac{1}{2x+2}+\frac{1}{2x-2}=\frac{1}{\left(x-1\right)}+\frac{1}{2\left(x+1\right)}+\frac{1}{2\left(x-1\right)}\)

MTC: 2(x-1)(x+1)

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

\(=\frac{2x+2+x-1+x+1}{2\left(x-1\right)\left(x+1\right)}=\frac{4x+2}{2\left(x-1\right)\left(x+1\right)}=\frac{2\left(x+1\right)}{2\left(x-1\right)\left(x+1\right)}=\frac{1}{x-1}\)

10 ) \(\frac{1}{x+3}+\frac{2}{x-3}+\frac{6}{x^2-9}=\frac{1}{x+3}+\frac{2}{x-3}+\frac{6}{\left(x-3\right)\left(x+3\right)}\)

MTC: (x-3)(x+3)

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

\(=\frac{x-3+2x+6+6}{\left(x-3\right)\left(x+3\right)}=\frac{3x-3+12}{\left(x-3\right)\left(x+3\right)}=\frac{3\left(x-1+4\right)}{\left(x-3\right)\left(x+3\right)}=\frac{3\left(x+3\right)}{\left(x-3\right)\left(x+3\right)}\)

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

Answer 2

[Nguyễn Ngọc Diệp]

4 / biến đổi dấu phân thức 

7x/x-2-14/x-2=7x-14/x-2

10/ MTC : (x-3) x ( x+3)

= 1x(x-3)+2x( x+3)+6/(x-3) x ( x+3)

bỏ  (x-3) x ( x+3) ở tử và mẫu còn

1+2+9 = 9

7chx nghĩ r 

HT~~~( sai thì xl hif^^)