Question

(7i)(-4i) a. -28i b. 28 c. -28 d. -32i

Answer 1

Hey!

Explanation:

↓↓↓↓↓↓↓↓↓↓

First, remove parenthesis.

$7i4i$

Secondly, multiple by the numbers.

$7*4=28$

$-28ii$

Third, apply exponents rule.

$-28i^2$

$i^2=-1$

$-28(-1)$

Finally, refine.

$=28$

Answer⇒⇒⇒⇒28

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