a

b

c

none of these

a

b

c

none of these

 $2\sqrt{2m+2}$  

 $\sqrt{2m+2}$  

 $3\sqrt{2m+2}$  

none of these

 $-5m\sqrt{3m}$  

 $5m\sqrt{3m}$  

 $15m\sqrt{m}$  

none of these

a

b

c

none of these

a

b

c

none of these

 $\frac{\sqrt{7m-7n}}{5}$  

 $\frac{7\sqrt{m-n}}{5}$  

 $7\sqrt{m-n}$  

 $\frac{7m-7n}{5}$  

 $10\sqrt{2}$  

 $13\sqrt{2}$  

 $15\sqrt{2}$  

 $23\sqrt{2}$  

 $\left(-10xy+18y\right)\sqrt{3xy}$  

 $2xy\sqrt{3y}+18x\sqrt{2y}-12\sqrt{3}$  

 $2xy\sqrt{3y}+18y\sqrt{2xy}-12xy\sqrt{3}$  

 $18y\sqrt{2xy}-10xy\sqrt{3y}$  

0

-2

-4

x - 4 

 $20\sqrt{5}$  

 $15\sqrt{5}$  

 $10\sqrt{5}$  

 $5\sqrt{5}$