Question

Which expression is equivalent to 298−−√⋅2√298·2 ?

Answer 1

Answer: 28 is the answer.

Explanation: Given expression is $2.\sqrt{98} \sqrt{2}$

Since, we can write,

⇒ $2.\sqrt{98} \sqrt{2}= 2.\sqrt{49\times 2} \times\sqrt{2}$

⇒$2.\sqrt{98} \sqrt{2}= 2.\sqrt{49}\times \sqrt{2} \times\sqrt{2}$

⇒$2.\sqrt{98} \sqrt{2}= 2.\sqrt{49}\times 2$ ( $\sqrt{2} \times \sqrt{2} =2$)

⇒$2.\sqrt{98} \sqrt{2}= 2\times7\times2$ ( Since, $\sqrt{49} =7$)

⇒$2.\sqrt{98} \sqrt{2}= 28$

Answer 2

$2 \sqrt{98} \cdot \sqrt{2} =2 \sqrt{49\times2} \cdot \sqrt{2} \\ \\ =2 \sqrt{49} \cdot \sqrt{2} \cdot \sqrt{2} =2\times7\times2 \\ \\ =28$