Question

Can someone help me out please:(:(

Answer 1

`\large\boxed{√(20)-√(80)=-2\sqrt5}`

Explanation:

`\text{Use}\ √(ab)=√(a)\cdot√(b)\\\\√(20)=√(4\cdot5)=\sqrt4\cdot\sqrt5=2\sqrt5\\\\√(80)=√(16\cdot5)=√(16)\cdot\sqrt5=4\sqrt5\\\\√(20)-√(80)=2\sqrt5-4\sqrt5=(2-4)\sqrt5=-2\sqrt5`