Question

Simplify the surd 3√ 20 +√ 45 ​

Answer 1

9/- 7dndusjjsjddkkdkdksksjdid

Answer 2

Answer:

9$\sqrt{5}$

Step-by-step explanation:

Using the rule of radicals

$\sqrt{a}$ × $\sqrt{b}$ ⇔ $\sqrt{ab}$

Simplify the radicals

$\sqrt{20}$

= $\sqrt{4(5)}$

= $\sqrt{4}$ × $\sqrt{5}$

= 2$\sqrt{5}$

$\sqrt{45}$

= $\sqrt{9(5)}$

= $\sqrt{9}$ × $\sqrt{5}$

= 3$\sqrt{5}$

Then

3$\sqrt{20}$ + $\sqrt{45}$

= 3(2$\sqrt{5}$ ) + 3$\sqrt{5}$

= 6$\sqrt{5}$ + 3$\sqrt{5}$

= 9$\sqrt{5}$