Question

已知X/Y=4/3,求(3X^2-5XY+2Y^2)/(2X^2+3XY-5Y^2)的值 "

Answer 1

X/Y=4/3,

X=4Y/3,

(3X^2-5XY+2Y^2)/(2X^2+3XY-5Y^2)

=(X-Y)(3X-2Y)/[(X-Y)(2X+5Y)]

=(3X-2Y)/(2X+5Y)

=[3*(4Y/3)-2Y]/[2*(4Y/3)+5Y]

=2Y/(23Y/3)

=6/23.