Question

Multiply (6 - 5)².
OA) 11+ 60i
B) 36 +25i
OC) 11-60i
OD) 36-25i

Answer 1

`\textsf{C)} \quad 11-60i`

Explanation:

`\textsf{Multiply }\: (6-5i)^2`

`\implies (6-5i)(6-5i)`

`\implies 6(6-5i)-5i(6-5i)`

`\implies 36-30i-30i+25i^2`

`\implies 36-60i+25i^2`

`\textsf{Remember that }i^2=-1:`

`\implies 36-60i+25(-1)`

`\implies 36-60i-25`

`\implies 36-25-60i`

`\implies 11-60i`