Question

Daine simplified the expression below.

8(1 + 2i) – (7 – 3i) = 1 + 5i

What mistake did Daine make?
He did not apply the distributive property correctly for 8(1 + 2i).
He did not distribute the subtraction sign correctly for 7 – 3i.
He added the real number and coefficient of i in 8(1 + 2i).
He multiplied the two complex numbers when he should have subtracted.

Answer 1

A. He did not apply the distributive property correctly for 8(1 + 2i).

Explanation:

Answer 2

Option (b).

Explanation:

Given expression is :

8(1 + 2i) – (7 – 3i)

Using distributive property :

8+16i-7+3i

Taking like terms together,

1+19i

(1+19i) is the simplified expression for the given expression. He did not apply distributive property correctly for 8(1 + 2i). He forgets to multiply 8 with 2i.