Question

simplify √45 - 3√20 + 4√5 ( step wise)

Answer 1

We can write
√45 = √9×5 = 3√5
3√20 = 3√4×5 = 3×2√5 = 6√5

3√5 - 6√5 + 4√5 = √5

Answer 2

Step-by-step explanation:

$\bf \underline{Solution-}$

$\sf{ \sqrt{45} - 3 \sqrt{20} + 4 \sqrt{5} }$

$\sf{ = \sqrt{9 \times 5} - 3 \sqrt{4 \times 5} + 4 \sqrt{5} }$

$\sf{ = 3 \sqrt{5} - 3 \times 2 \sqrt{5} + 4 \sqrt{5} }$

$\sf{ = (3 - 6 + 4) \sqrt{5} }$

$\sf{ = \sqrt{5} } \: \: \: \: \bf{Ans.}$