S.N. Chhibber Solutions for Chapter: Identities, Exercise 1: Exercise

If $3y-\frac{1}{3y}=3$, find the value of  $9y^2+\frac{1}{9y^2}$

If $3y-\frac{1}{3y}=3$, find the value of  $81y^4+\frac{1}{81y^4}$

If $x+2y=9$ and $xy=7$, find the value of $x^2+4y^2$.

Find the value of $25x^2-70xy+49y^2$, when $x=15$ and $y=5$

If $x-y=16$ and $x^2+y^2=400$, find $xy$.

If $x^2+y^2=74$ and $xy=35$, find $x+y$. 

The area of a square is $9x^2+24xy+16y^2$. Find the side of the square.

The area of a circle is given by the expression $9\mathrm{\pi }{x}^2-12\mathrm{\pi }x+4\mathrm{\pi }$. If the radius of the circle is $r \mathrm{cm}$, find the value of $r$ when $x=4 \mathrm{cm}$.