Question

if QX=xy/2, px=xz/2 and qx=px than show that xy=yz

Answer 1

acc to question, 

qx = xy/2  and  px = xz/2   and qx=px  which means we can write,

xy/2 = xz/2 . Now from both the sides we can see the 2 in the denominator gets cancelled and we are left with the expression as : xy = xz which is the required expression to be proved. Hence proved.

Basically what we have used here is the concept of substitution method i.e. we have substituted the equation in mid with it's equivalent value.

Answer 2

Please try to post complete question.
I hope correct question is:
In the figure, If QX=xy/2, px=xz/2 and qx=px than show that xy=yz

Solution:
In figure:
Qx=1/2xy
xy=2Qx --------equation(1)

Now Px= 1/2 xZ
xZ=2Px ------------equation(2)
Now given Qx=xP
Now substitute the above value in equation 2 we get:
xZ=2Qx------equation (3)
Equating equation 1 and 3
We get
xy=xz
Hence proved