Question

The modulus of (3 + 4i)4 is _____.

5
20
125
625

Answer 1

(3+4i)*4 = 3*4+4i*4 = 12+16i

The complex number 12+16i is in the form a+bi where a = 12 and b = 16

m = modulus
m = distance from (0,0) to (a,b)
m = sqrt(a^2+b^2)
m = sqrt(12^2+16^2)
m = sqrt(144+256)
m = sqrt(400)
m = 20

Answer: 20