Question

Which of the following expressions is equal to x^2+9
A) (x+3i)(x-6i)
B) (x+3i)(x-3i)
C) (x-3i)^2
D) (x+3i)^2

Answer 1

the correct option is b...
method= x−3i)(x+3i)(x-3i)(x+3i)

Expand (x−3i)(x+3i)(x-3i)(x+3i) using the FOILMethod.
xx+x(3i)−3ix−3i(3i)xx+x(3i)-3ix-3i(3i)

Simplify and combine like terms.
x2+9

Answer 2

B. (x+3i)(x-3i)

Explanation: Ap3x