Question

Help, please! Struggling!

Your friend multiplied complex numbers and expression as shown. Find the error in your friend’s work. Then factor the expression correctly.

(4-7i)(4+7i)=16+28c-28i+49i2
= 16-49
= -33

Answer 1

65

Explanation:

(4-7i)(4+7i) =16 + 28i-28i -49i^2 ➡16 - 49i^2

16 + 49 = 65

the fault here is i^2= -1 and -1 multiplied by -49 is +49 not -49