Question

If u = -8i + 7j, what is the magnitude of -5u? Simplify any radicals.​

Answer 1

Answer:

$- 5 \sqrt{113}$

Step-by-step explanation:

Find the magnitude of the complex number

Notice the magnitude is equal to

$u = \sqrt{ {a}^{2} + {b}^{2} }$

where a is the real number and b is the imaginary number.

Substitute

$u = \sqrt{ - 8 {}^{2} + 7 {}^{2} }$

$u = \sqrt{64 + 49}$

$u = \sqrt{113}$

Multiply this by -5

$- 5 \sqrt{113}$