Question

Find the product of (x + 9i)^2

Answer 1

@chetan552

Answer 2

@solomonzelman please help

Answer 3

It works the same way as (a+b)^2 just you need to know that i^2=-1

Answer 4

can you explain step by step please? @Andras

Answer 5

(a+b)^2=a^2+2ab+b^2
This is the foundation of algebra so I really hope you know that!

(x + 9i)^2= x^2+2x9i+(9i)^2 = x^2+18xi +81i^2=x^2+18xi-81

Answer 6

@Andras thank you so much! can you help me in 2 more? I know how to start it but the foil part is what mostly throws me off plus i started florida virtual late so im a bit lost in what we are doing

Answer 7

I am going to bed soon. It is just past midnight here. Post a new question and I am sure some1 will help you out.

Answer 8

Find the product of (x – 2i)^2
Find the product of (x + (3+5i))^2

Thats super sweet of you, thank you so much! @Andras

Answer 9

(x – 2i)^2
x^2-2x2i+(2i)^2=x^2-4xi-4

Answer 10

(x + (3+5i))^2
x^2+2x(3+5i)+(3+5i)^2

This has a sub-problem within:
(3+5i)^2=9+15i-25

x^2+2x(3+5i)+(3+5i)^2=
x^2+6x+10xi+9+15i-25=
x^2+6x+10xi+15i-16

Answer 11

@Andras thank you so much!! :)

Answer 12

Hope you think it through at least and not just copy-paste for your homework. :0

Answer 13

@Andras dont worry im reviewing it and noticing how it gets to the final answer!

Answer 14

Its nothing but (a+b)^2 formula...
(a+b)^2= a^2+b^2+2ab

hear a=x , b=9i
and also dont forget that in the expantion you will see i^2
dont worry about that just repace i^2 with -1 you will get the answer....