Simplify: (5-2i)(3+i)?

Question

Simplify: (5-2i)(3+i)



a. 17 - i

b. 15 + i

c. -17 + i





Simplify: 3/i
(Division)



a. -3i

b. -3/i

c. 3i

Answer 1

Question 1
(5 - 2i ((3 + i)
15 + 5i - 6i + 2
17 - i
Option a)

Question 2
3 / i = 3 i / (i ²) = 3 i / (-1) = - 3 i
Option a)

Answer 2

All you really have to do is F.O.I.L

(5-2i)(3+i)
15+5i-6i-2i^2 remember that i^2= -1
15-i-2(-1)
15-i+2
17-i

if you don't understand F.O.I.L
you can always do this:

5(3+i) -2i(3+i) just distribute here
15+5i-6i - 2i^2
15-i + 2
17-i
The Answer is A

you have to multiply by the conjugate or the opposite which is
-i
3/i x -i/-i
-3i/i^2
-3i/-1
3i
The answer is C
Hope this helps =)

Answer 3

In the first question you have to cross multiply:

(5-2i)(3+i)
=15+5i-6i-2i^2
=-2i^2-i+15

I do not see the answer....

And there is nothing to simplify in the second questionl

Answer 4

15+5i-6i-2i^2=15-i+2=17-i.......a

3/i multiply top and bottom by i
you get 3i/i^2=-3i....a

Answer 5

(5-2i)(3+i)
FOIL
15 + 5i - 6i -2i²
15 +5i - 6i -2(-1)
15 + 5i - 6i +2
COMBINE LIKE TERMS
=17 - i

3/i
MULTIPLY NUMERATOR AND DENOMINATOR BY i
= (3i) / (i²)
=(3i) /(-1)
= -3i

Answer 6

1) Use FOIL

(5 - 2i)(3 + i)
FIRST, OUTSIDE, INSIDE, LAST
15 + 5i + (-6i) + (-2i^2)

15 + (-i) + (2i^2)

I think...

Answer 7

F.O.I. L.