Question

Write the product in standard form.

Answer 1

( 9 + 5i)( 9 + 8i)

Answer 2

41+117i

Answer 3

Steps?

Answer 4

18 =13I

Answer 5

the foiling method, do you know what that is?

Answer 6

what do you do after (9*9)+(9*5i)+(9*8i)+(8i*5i)

Answer 7

(a+b)(c+d)=ab+bc+ad+bd

Answer 8

oh i just did it on the calculator, thats all you do there really is no steps

Answer 9

multiply them

Answer 10

do you know the meaning of i ?

Answer 11

look im write ok

Answer 12

81+157i i got this and i know its wrong can you khow steps so i can compare?

Answer 13

81+45i+72i-40

Answer 14

i gave you the right answer

Answer 15

isnt it 40i

Answer 16

i^2=-1

Answer 17

can i get my metal now ;)

Answer 18

i know you gave me the right answer but i need to know what i did wrong because i didnt get that

Answer 19

i is the square root of -1
so i*i = -1

Answer 20

(9*9)+(9*5i)+(9*8i)+(8i*5i)
81 +45i +72i+40i^2
i^2 is -1
so
81-40 + (45+72)i
simplify
41+112i

Answer 21

why 40^2?

Answer 22

its 117i, phi you got it wrong

Answer 23

@ilikephysics2 is correct

Answer 24

thats why 8i * 5*i = 40 i*i =40 *(-1)= -40

Answer 25

typo, 117i

Answer 26

i got it thanks guys just one questions why you do 40 ^2

Answer 27

it is 40 times i*i
i^2 which is -1

Answer 28

so do FOIL, but with the trick that i*i can be replaced with -1

Answer 29

oh thank you @phi so when ever its i*i you have to change it to a negative?

Answer 30

yes. i is short for sqrt(-1)
sqrt(-1)*sqrt(-1)= -1

so keep i's but replace i*i (or i^2) with -1

Answer 31

okay i get it thanks to all