SOLUTION: Given the equation (x+yi)(4+3i)=7-4i Find x and y ?

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Question 1143622: Given the equation (x+yi)(4+3i)=7-4i
Find x and y ?

Found 2 solutions by Edwin McCravy, Alan3354:
Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!
%28x%2Byi%29%284%2B3i%29=7-4i

FOIL out the left side:

4x%2B3xi%2B4yi%2B3yi%5E2=7-4i

Use the fact that i²= -1 to substitute (-1) for i²

4x%2B3xi%2B4yi%2B3y%28-1%29=7-4i

Simplify the third term on the left:

4x%2B3xi%2B4yi-3y=7-4i

The 2 REAL terms (that DON'T have i) on the left must 
equal the REAL term on the right (that DOESN'T have i) so:

4x-3y=7

The IMAGINARY terms on the left (that DO have i) must 
equal the IMAGINARY term on the right (that DOES have i), so:

3xi%2B4yi=-4i

Divide through by i:

3x%2B4y=-4

So we have the system of equations:

system%284x-3y=7%2C3x%2B4y=-4%29

Solve that system (preferably by the elimination method):

x=16%2F25 and y=-37%2F25

Edwin

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Given the equation (x+yi)(4+3i)=7-4i
Find x and y ?
----------------
(x+yi)(4+3i)= 4x+3xi +4yi-3y
4x-3y + i*(3x+4y) = 7-4i
------
4x-3y = 7
3x+4y = -4
=================
Can you do the rest?