45% of 300 + $$\sqrt {?} $$ = 56% of 750 - 10% of 250

Let 45% of 300 + $$\sqrt {x} $$ = 56% of 750 - 10% of 250
Then,
$$\left( {\frac{{45}}{{100}} \times 300} \right) + \sqrt x = \left( {\frac{{56}}{{100}} \times 750} \right)$$       $$ - \left( {\frac{{10}}{{100}} \times 250} \right)$$
$$\eqalign{ & \Rightarrow 135 + \sqrt x = 420 - 25 \cr & \Rightarrow \sqrt x = 260 \cr & \Rightarrow x = {\left( {260} \right)^2} \cr & \Rightarrow x = 67600 \cr} $$