Posted by Breanna on Monday, June 22, 2009 at 10:40pm.
Simplify: Write answers in the form of a + bi, where a and b are real numbers.
a. (12i)(1+3i)
b. (35i)(82i)

Algebra  bobpursley, Monday, June 22, 2009 at 10:59pm
Use FOIL to multiply them out.

Algebra  Breanna, Monday, June 22, 2009 at 11:15pm
IS this correct, i notice that i^2 = 1 what does this mean?
(12i)(1+3i)
=1+3i2i6i^2
=1+ i6i^2
= 1+i6i 
Algebra  bobpursley, Monday, June 22, 2009 at 11:51pm
no, 6i^2 is 6*(1)
so the last term is +6 and the final answer is
7+i 
Algebra  Breanna, Tuesday, June 23, 2009 at 12:11am
So did I do any of this correct? What do I need to fix?

Algebra  MathMate, Tuesday, June 23, 2009 at 12:56am
You have basically done it correctly, but omitted to change the sign of the last term because i^{2}=1
(12i)(1+3i)
=1+3i2i6i^2
=1+ i6i^2
= 1+i +6i 
Algebra  MathMate, Tuesday, June 23, 2009 at 12:57am
Oops, it should read:
(12i)(1+3i)
=1+3i2i6i^2
=1+ i6i^2
= 1+i +6
=7+i