Solution:
The given complex expression is,
→(5+3 i) - (5+3 i)(5-5 i)
Keep in mind, i=√-1, i²= -1
=(5 + 3 i)[1- (5-5 i)]
=(5 + 3 i)[1-5+ 5 i]
= (5 + 3 i)[-4 + 5 i]
=5 × (-4 + 5 i) + 3 i×(-4 + 5 i)→→Used the identity, (a+b)×(c+d)=a×(c+d)+b×(c+d), Also Used distributive property of multiplication over addition and subtraction.
= -20 + 25 i-12 i +15 i²
= - 20 + 13 i-15
= -35 + 13 i
