Question

Evaluate 4 root -4+5 root-9-3root-16

Answer 1

$Given \: 4\sqrt{-4} + 5\sqrt{-9} - 3 \sqrt{-16} \\= 4\sqrt{ (2i)^{2}} + 5\sqrt{ (3i)^{2}} -3\sqrt{ (4i)^{2}} \\= 4 \times (2i) + 5\times (3i) - 3\times (4i) \\= 8i + 15i - 12i \\= ( 8+15-12)i\\= 11i$

Therefore.,

$\red{4\sqrt{-4} + 5\sqrt{-9} - 3 \sqrt{-16} }\green{=11i}$

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