Question

Tìm x biết:

a) x/x+1 = x+5/x+7

b) x+7/x+4 = x-1/x-2

c) x+2/x-2 = x-3/x+3

 

Answer 1

a) \(\frac{x}{x+1}=\frac{x+5}{x+7}\)

\(=>x\left(x+7\right)=\left(x+1\right).\left(x+5\right)\)

\(=>x^2+7x=x^2+6x+5\)

\(=>x^2+7x-x^2-6x-5=0\)

\(=>x-5=0\)

\(=>x=5\)

vay \(x=5\)

b) \(\frac{x+7}{x+4}=\frac{x-1}{x-2}\)

\(=>\left(x+7\right)\left(x-2\right)=\left(x+4\right)\left(x-1\right)\)

\(=>x^2+5x-14=x^2+3x-4\)

\(=>x^2+5x-14-x^2-3x+4=0\)

\(=>2x-10=0\)

\(=>2\left(x-5\right)=0\)

\(=>x-5=0\)

\(=>x=5\)

vay \(x=5\)

c) \(\frac{x+2}{x-2}=\frac{x-3}{x+3}\)

\(=>\left(x+2\right)\left(x+3\right)=\left(x-2\right)\left(x-3\right)\)

\(=>x^2+5x+6=x^2-7x+6\)

\(=>x^2+5x+6-x^2+7x-6=0\)

\(=>12x=0\)

\(=>x=0\)

vay \(x=0\)

Answer 2

đáp số là 0 , đúng thì cho mình xin đúng nhé cảm ơn