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.