Answered

A student is asked to multiply [tex]$2i$[/tex] and [tex]$(-8i + 3)$[/tex] and write the resulting product in the form of [tex][tex]$a + bi$[/tex][/tex]. Identify in which step the student made the error.

Step 1: [tex]2i(-8i) + 2i(3)[/tex]

Step 2: [tex]16i^2 + 6i[/tex]

Step 3: [tex]16(-1) + 6i[/tex]

Step 4: [tex]-16 + 6i[/tex]

A. Step 1

B. Step 2

C. Step 3

D. Step 4



Answer :

To analyze the solution step by step, let's begin by understanding the original expression and follow the student's steps:

The initial problem is to multiply [tex]\(2i\)[/tex] by [tex]\((-8i + 3)\)[/tex].

Step 1: Distribute [tex]\(2i\)[/tex] across [tex]\((-8i + 3)\)[/tex]:

[tex]\[ 2i (-8i) + 2i (3) \][/tex]

Step 2: Compute each term.

- For the first term: [tex]\( 2i \times -8i = -16i^2 \)[/tex]
- For the second term: [tex]\( 2i \times 3 = 6i \)[/tex]

Putting them together, we get:

[tex]\[ -16i^2 + 6i \][/tex]

Step 3: Substitute [tex]\(i^2\)[/tex] with [tex]\(-1\)[/tex]:

[tex]\[ -16(-1) + 6i \][/tex]

Step 4: Simplify the expression:

[tex]\[ 16 + 6i \][/tex]

So:

[tex]\[ 16 + 6i \][/tex]

Comparing this solution with the expected outputs:

The correct product in the form of [tex]\(a + bi\)[/tex] is [tex]\( 16 + 6i \)[/tex].

Here are the steps where the student computationally did everything right. The error is not evident because the final expression [tex]\(16 + 6i\)[/tex] matches the expected product.

Thus, no step contains a computational error.

Other Questions