Question

Write V-16 + V49 as a complex number in the form of a + bi.
A. 7 + 4i
B. 7-41
C.-4+ 71
D.
4 + 71
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Answer 1

Answer:

A. 7 + 4i

Step-by-step explanation:

$\text{Use:}\\\\i=\sqrt{-1}\\\\\sqrt{ab}=\sqrt{a}\cdot\sqrt{b}\\\\\sqrt{a}=b\iff b^2=a\\\\=========================$

$\sqrt{-16}+\sqrt{49}=4i+7=7+4i\\\\\text{because}\\\\\sqrt{49}=7\ \text{because}\ 7^2=49\\\\\sqrt{-16}=\sqrt{(16)(-1)}=\sqrt{16}\cdot\sqrt{-1}=4i\qquad /\sqrt{16}=4\ \text{because}\ 4^2=16/$