Question

Simplify the surd 3√ 20 +√ 45 ​

Answer 1

9/- 7dndusjjsjddkkdkdksksjdid

Answer 2

9
`√(5)`

Explanation:

Using the rule of radicals

`√(a)` ×
`√(b)` ⇔
`√(ab)`

Simplify the radicals

`√(20)`

=
`√(4(5))`

=
`√(4)` ×
`√(5)`

= 2
`√(5)`

`√(45)`

=
`√(9(5))`

=
`√(9)` ×
`√(5)`

= 3
`√(5)`

Then

3
`√(20)` +
`√(45)`

= 3(2
`√(5)` ) + 3
`√(5)`

= 6
`√(5)` + 3
`√(5)`

= 9
`√(5)`