Question

2root7+6roor7 - 12root28​

Answer 1

$Given \: 2\sqrt{7} + 6\sqrt{7} - 12 \sqrt{28}$

$= 2\sqrt{7} + 6\sqrt{7} - 12 \sqrt{4\times 7}$

$= 2\sqrt{7} + 6\sqrt{7} - 12 \times 2\sqrt{ 7}$

$= 2\sqrt{7} + 6\sqrt{7} - 24\sqrt{ 7}$

$= (2 + 6 - 24)\sqrt{ 7}$

$= (8-24)\sqrt{7}$

$= -16\sqrt{7}$

Therefore.,

$\red{2\sqrt{7} + 6\sqrt{7} - 12 \sqrt{28}} \green { = -16\sqrt{7}}$

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Answer 2

Answer:

$Given \: 2\sqrt{7} + 6\sqrt{7} - 12 \sqrt{28}$

$= 2\sqrt{7} + 6\sqrt{7} - 12 \sqrt{4\times 7}$

$= 2\sqrt{7} + 6\sqrt{7} - 12 \times 2\sqrt{ 7}$

$= 2\sqrt{7} + 6\sqrt{7} - 24\sqrt{ 7}$

$= (2 + 6 - 24)\sqrt{ 7}$

$= (8-24)\sqrt{7}$

$= -16\sqrt{7}$

Therefore.,

$\red{2\sqrt{7} + 6\sqrt{7} - 12 \sqrt{28}} \green { = -16\sqrt{7}}$

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