Question

.

Answer 1

tried this ?

Answer 2

u know what i is , right ?>

Answer 3

foil it.

Answer 4

what u got ? show us here...

Answer 5

(-4i)(5i) = -20 i^2
and i^2 = ?

Answer 6

(9-4i)(2+5i).
= 9*2 +9*5i -4i*2 -(4i)(5i)
= .... ?

Answer 7

if u know what i=...?
the u might be knowing what i^2= ?

Answer 8

(9-4i)(2+5i).
= 9*2 +9*5i -4i*2 -(4i)(5i)
got this much ?

Answer 9

i^2 = -1

Answer 10

\(i=\sqrt{-1} \\ i^2=1\)

Answer 11

(9-4i)(2+5i).
= 9*2 +9*5i -4i*2 -(4i)(5i)
= 18 + 45 i -8i +20
= ?

Answer 12

\((-4i)(5i)=-20i^2 =-20(-1)=20\)

Answer 13

yes, absolutely :)

Answer 14

did u undersatnd all steps clearly ?

Answer 15

you all are most welcome ^_^