Question

cho 5*x​ =3*y  Tinh

\(\frac{5x^2+3y^2}{10x^2-3y^2}\)

 

Answer 1

5*x=3*y => x/3=y/5 => x=3k,y=5k

thay vào: 5x²+3y²/10x²-3y²=5.(3k)²+3.(5k)²/10.(3k)²-3(5k)²=45k²+75k²/90k²-75k²=k².(45+75)/k².(90+75)=120/165=8/11

Answer 2

Cho hai so x,y khac 0 thoa man : 3x - y = 3z ; 2x + y = 7z

Tinh : B= \(\frac{x^2-2xy}{x^2+y^2}\)