Simplify: Write answers in the form of a + bi, where a and b are real numbers.

a. (1-2i)(1+3i)

b. (3-5i)(8-2i)

Use FOIL to multiply them out.

IS this correct, i notice that i^2 = -1 what does this mean?

(1-2i)(1+3i)
=1+3i-2i-6i^2
=1+ i-6i^2
= 1+i-6i

no, 6i^2 is 6*(-1)

so the last term is +6 and the final answer is
7+i

So did I do any of this correct? What do I need to fix?

You have basically done it correctly, but omitted to change the sign of the last term because i2=-1

(1-2i)(1+3i)
=1+3i-2i-6i^2
=1+ i-6i^2
= 1+i +6i

Oops, it should read:

(1-2i)(1+3i)
=1+3i-2i-6i^2
=1+ i-6i^2
= 1+i +6
=7+i

Give me answers of 2.6 of 9 class