Question

tìm x trong tỉ lệ thức : \(\frac{x-2}{x-1}=\frac{x+4}{x+7}\)

Answer 1

\(\Leftrightarrow\left(x-2\right)\left(x+7\right)=\left(x-1\right)\left(x+4\right)\Leftrightarrow x^2+5x-14=x^2+3x-4\Leftrightarrow2x=10\Leftrightarrow x=5\)

Answer 2

x² ở đâu có vạy bạn 

Answer 3

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

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

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

\(\Leftrightarrow x^2+15=x^2+3x-4+14\)

\(\Leftrightarrow x^2+15=x^2+3x+10\)

\(\Leftrightarrow x^2+5x-\left(x^2+3x\right)=x^2+3x+10-\left(x^2+3x\right)\)

\(\Leftrightarrow2x=10\)

=> x = 5