Question

(3-4i) (7+5i)=?help me pls​

Answer 1

(3 - 4i)(7 + 5i) = 3 * 7 + 3 * 5i - 7 * 4i - 4i * 5i = 21 + 15i - 21i - 20i² =

= 21 - 6i - 20 * (- 1) = 21 - 6i + 20 = 41 - 6i

Answer 2

Ответ:

41-13i

Объяснение:

(3-4i)(7+5i)

3×7+3×5i-4i×7-4i×5i

25+15i-28i-20i²

21+15i-28i-20×(-1)

21+15i-28i+20

41-13i

Answer 3

Of course, I'd be happy to help you with that multiplication!

To multiply two complex numbers, you can use the distributive property, just like you would with regular algebra. Here's how you can multiply (3 - 4i) and (7 + 5i):

(3 - 4i) * (7 + 5i)

First, let's use the distributive property to multiply the terms:

= 3 * 7 + 3 * 5i - 4i * 7 - 4i * 5i

= 21 + 15i - 28i - 20i^2

Now, remember that i^2 is equal to -1:

= 21 + 15i - 28i + 20

Now combine like terms:

= 41 - 13i

So, (3 - 4i) * (7 + 5i) = 41 - 13i.