Rewrite the following expression in the form [tex]\(a \sqrt{10}\)[/tex], where [tex]\(a\)[/tex] is an integer:

[tex]\[ 6 \sqrt{5}(\sqrt{8} + \sqrt{18}) \][/tex]

Find the value of [tex]\(a\)[/tex].



Answer :

To simplify the expression [tex]\( 6 \sqrt{5} (\sqrt{8} + \sqrt{18}) \)[/tex] and express it in the form [tex]\( a \sqrt{10} \)[/tex], let's go through the steps systematically.

1. Simplifying [tex]\(\sqrt{8}\)[/tex]:
[tex]\[ \sqrt{8} = \sqrt{4 \cdot 2} = \sqrt{4} \cdot \sqrt{2} = 2 \sqrt{2} \][/tex]

2. Simplifying [tex]\(\sqrt{18}\)[/tex]:
[tex]\[ \sqrt{18} = \sqrt{9 \cdot 2} = \sqrt{9} \cdot \sqrt{2} = 3 \sqrt{2} \][/tex]

3. Adding the simplified square roots:
[tex]\[ \sqrt{8} + \sqrt{18} = 2 \sqrt{2} + 3 \sqrt{2} = (2 + 3) \sqrt{2} = 5 \sqrt{2} \][/tex]

4. Multiplying by [tex]\( 6 \sqrt{5} \)[/tex]:
[tex]\[ 6 \sqrt{5} \cdot 5 \sqrt{2} \][/tex]

Combine the constants and the square roots separately:
[tex]\[ 6 \cdot 5 \cdot \sqrt{5} \cdot \sqrt{2} = 30 \cdot \sqrt{10} \][/tex]

5. Therefore, the expression [tex]\( 6 \sqrt{5} (\sqrt{8} + \sqrt{18}) \)[/tex] can be written as [tex]\( 30 \sqrt{10} \)[/tex].

We can now compare this with [tex]\( a \sqrt{10} \)[/tex] and see that [tex]\( a = 30 \)[/tex].

Thus, the value of [tex]\( a \)[/tex] is:
[tex]\[ a = 30 \][/tex]