The simplified solution to, (-3i)(7i)(-i) is -21i. The detailed solution for the same is added below:

Simplify (-3i)(7i)(-i)

Solution:

(-3i)(7i)(-i)

= (3 × 7) × (-i × i × -i)

= 21 × i³

Since, i³ = -i

⇒ 21 × i³ = 21 × -i

= -21i

Similar Questions

Question 1. Simplify: (4 + i)(7 + 3i).

Solution:

Given,

• (4 + i)(7 + 3i)

= 4(7 + 3i) + i(7 + 3i)

= 28 + 12i + 7i + 3i²

= 28 + 19i + 3(-1)

= 28 – 3 + 19i

= 25 + 19i

Question 2. Simplify: (2 + i)(-5).

Solution:

Given,

• (2 + i)(-5)

= 2(-5) + i(-5)

= -10 – 5i

Question 3. Simplify: (4 + 8i)(4 – 8i).

Solution:

Using algebraic identity (a + b)(a – b) = a² – b²

Given,

• (4 + 8i)(4 – 8i)

= 4² – (8i)²

= 16 – 8²i²

= 16 – 64(-1)

= 16 + 64

(4 + 8i)(4 – 8i) = 80

Question 4. Evaluate: (5 + 6i)(6 – 5i).

Solution:

Given,

•  (5 + 6i)(6 – 5i)

= 5(6 – 5i) + 6i(6 – 5i)

= 30 – 25i + 36i – 30i²

= 30 + 11i – 30(-1)

(5 + 6i)(6 – 5i) = 60 + 11i

Question 5. Simplify: (-13i)(17i)(-i).

Solution:

Given,

• (-3i)(7i)(-i)

= (13 × 17) × (-i × i × -i)

= 221 × i³

Since, i³ = -i

⇒ 221 × i³ = 221 × -i

= -221i