Question

evaluate
15/√10+√20+√40-√5-√80
where
√5 =2.236
√10=3.162
​

Answer 1

Answer:

4.359

Step-by-step explanation:

$\frac{15}{ \sqrt{10} } + \sqrt{20} + \sqrt{40} - \sqrt{5} - \sqrt{80} \\ = \frac{15 \times \sqrt{10} }{ \sqrt{10} \times \sqrt{10} } + \sqrt{2 \times 2 \times 5} + \sqrt{2 \times 2 \times 2 \times 5} - \sqrt{5} - \sqrt{2 \times 2 \times 2 \times 2 \times 5} \\ = \frac{15 \sqrt{10} }{10} + 2 \sqrt{5} + 2 \sqrt{10} - \sqrt{5} - 4 \sqrt{5} \\ = \frac{3 }{2} \sqrt{10} + 2 \sqrt{10} + 2 \sqrt{5} - \sqrt{5} - 4 \sqrt{5} \\ = \frac{3 \sqrt{10} + 4 \sqrt{10} }{2} + \sqrt{5} - 4 \sqrt{5} \\ = \frac{7 \sqrt{10} }{2} - 3 \sqrt{5} \\ = \frac{7 \times 3.162}{2} - 3 \times 2.236 \\ = 7 \times 1.581 - 6.708 \\ = 11.067 - 6.708 \\ = 4.359$