Question

Write the expression in the form a+bi.
i(3+4i)^2

Answer 1

expand (3+4i)^2 using the identity\[(a+b)^2=a^2+2ab+b^2\]

Answer 2

then multiply it by i

Answer 3

Use \((a+b)^2=a^2+2ab+b^2\) and \(i^2=-1\).

Answer 4

so it should be 9+12i+16i^2 right?

Answer 5

remeber i^2 is real = -1, so you can simplify some more

Answer 6

remember i^2 is real = -1, so you can simplify some more

however, you lost the bubble some where because your expression
9+12i+16i^2 = -7+12i does not match
i*(3+4i)^2