Question

Simplify the complex number expression:
-5(1+2i)+3i(3-4i)

Answer 1

Answer:

21 × 7i

This question should be solved according to BODMAS

Answer 2

Answer:

7 - i

Step-by-step explanation:

Standard form of a complex number is a + bi. The a represents the real part and bi represents the imaginary part.

Keep in mind that i² = -1.

To simplify this complex number expression first distribute -5 inside the parentheses.

-5(1 + 2i)

⇒ -5 - 10i

Now distribute 3i inside the parentheses.

3i(3 - 4i)

⇒ 9i - (-12)

Put both of these expressions together and combine like terms as normal.

-5 - 10i + 9i + 12

Add the like terms;

-5 + 12 - 10i + 9i

⇒ 7 - i

We are left with 7 - i as our answer. This is in the standard form of a complex number, therefore, it is our final answer.