Question

Can someone tell me the answer and explain how you got that answer so i can do future problems on my own?

Answer 1

we are given
(7 + 4i) (2-3i)
we can use the distributive property to multiply the two.

first we take the first number from the first set of numbers (7) and multiply it by the first number of the second set of numbers (2) to get 14

then we take the first number again (7) but multiply it by the second number of the second set of numbers (-3i) to get -21i

you do the same with the second number in the first set of numbers (multiplying it by 7 and then by -3i)

you should get an answer of

14 - 21i +8i - 12i²
14 -13i - 12i²

since i=
`√(-1)`, i² is equal to -1

so plug in -1 for i² and you should get

14 -13i - 12(-1)
14 - 13i +12
26 -13i

A) 26-13i should be your answer

hope this helped!

Answer 2

You will FOIL this out like you would any other set of binomials that need to be multiplied. Begin by multiplying the 7 and the 2 to get 14. Then go back to the 7 and this time multiply it by -3i to get -21i. Then move to the 4i. 4i times 2 is 8i. Then go back to the 4i and multiply it by -3i to get -12i^2. Putting all that together we have 14-21i+8i-12i^2. Combine like terms to simplify a bit before we deal with the i^2 term. 14-13i-12i^2. i^2 = -1, so let's make that substitution. 14-13i-12(-1). Doing that multiplication we have 14-13i+12. We can combine like terms once more to get 26-13i as our final answer. First choice above.