Question 149761: Please can someone help me with this problem: For i= -1, 3i(2+5i)= x+6i,then x=?
This is how i tried to solve the problem: 3ix2=6i,and 3ix5i=15i,now i combine 6i+ 15i = x + 6i, I broke down the problem by adding 6i + 15i= 21i=x+6i, then i made the 21i negative on both sides:
21i = x + 6i
-21i -21i= -15, is this correct?
Found 3 solutions by ankor@dixie-net.com, kmcruz09, ayman11:
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! 3i(2+5i)= x+6i,then x=?
;
Not quite: 3i * 5i = 15i^2; we know i^2 = -1. so we have:
6i + 15i^2 = x + 6i
:
6i + 15(-1) = x + 6i
which is:
6i - 15 = x + 6i
:
6i - 6i - 15 = x
:
x = -15
:
Actually much simpler than you made it to be:
Answer by kmcruz09(38)  (Show Source):
Answer by ayman11(2) (Show Source):
You can put this solution on YOUR website! 3i(2+5i) = x + 6i
3i .2 + 3i . 5i = x + 6i
6i + 15 (i)^2 = x + 6 i
6 i - 15 = x + 6i by adding ( - 6 i ) to both sides
- 6 i -6i
-15 = x
|
|
|
