Question

Multiply and simplify: 3i(4 - 3i) - i (2 + i)

Answer 1

10 + 10i

Apply Multiplicative Distribution Law: 12i - 9 x i^2 - 2i - i^2

Rewrite by definition: i^2 = -1:12i - 9 x (-1) -2i - (-1)

Remove the parentheses: 12i + 9 - 2i + 1

Combine like terms: 10 + 10i

Answer 10 + 10i

Answer 2

10 + 10i

Explanation:

Given expression:

`3i(4 - 3i) - i (2 + i)`

Expand:

`\implies 12i-9i^2-2i-i^2`

`\implies 12i-2i-9i^2-i^2`

`\implies 10i-10i^2`

Apply the imaginary number rule i² = -1 :

`\implies 10i-10(-1)`

Simplify:

`\implies 10i+10`

Rewrite in standard complex form a + bi:

`\implies 10+10i`