Question

What is the following sum? 4 sqrt 5 + 2 sqrt 5

Answer 1

`6√(5)`

Explanation:

sum of 4 sqrt 5 + 2 sqrt 5

`4√(5) + 2√(5)`

Both terms have same square root(5)

So they are like terms.

When they are like terms, we add the number outside the square root.

Square root remains the same.

`a√(x) + b√(x)=(a+b)√(x)`

`4√(5) + 2√(5)=(4+2)√(5)=6√(5)`

Answer 2

The rule is
`a √(b)+c √(b)=(a+c) √(b)`, so


`4 √(5)+2 √(5) = 6 √(5)`