Solve the following equations:
2x2−xy+y2=2y,2x2+4xy=5y.
Given, 2x2+4xy=5y .......(i)
Also given 2x2−xy+y2=2y
Substituting y on the R.H.S from (i)
2x2−xy+y2=2(2x2+4xy5)⇒10x2−5xy+5y2=4x2+8xy⇒6x2−5xy+5y2=8xy⇒6x2−5xy+2xy=8xy−5y2+2xy⇒6x2−3xy=10xy−5y2⇒3x(2x−y)=5y(2x−y)⇒3x(2x−y)−5y(2x−y)=0⇒(3x−5y)(2x−y)=0⇒3x=5y,2x=y
Substituting y in (i), we get
(1). 3x=5y
⇒y=3x5
Therefore, 2x2+4x.3x5=5.3x5
⇒22x2=15x⇒22x2−15x=0⇒x(22x−15)=0⇒x=0,1522
y=3x5x=0⇒y=0x=1522⇒y=922
(2). y=2x
2x2+4x(2x)=5(2x)⇒10x2−10x=0⇒10x(x−1)=0⇒x=0,1y=2xx=0⇒y=0x=1⇒y=2
So, the values of x are 0,1,1522 and the corresponding values of y are 0,2,922.