If a, b, c are in AP and x, y, z are in GP then prove that the value of xb - c. yc - a. za - b is 1.

To prove: xb - c. yc - a. za - b = 1….(i)


It is given that a,b,c are in A.P.


2b = a + c…(ii)


And x,y,z, are in G.P.


y2 = xz


x = y2/z


Substitute this value of x in equation (i),we get


L.H.S =






y0.z0…(Using equation (i))


= 1 = R.H.S


Hence, proved that . If a, b, c are in AP and x, y, z are in GP then xb - c. yc - a. za - b = 1


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