1. ## Complex Numbers...Find x

Solve for x: (3 + 2i) + (4 + xi)= 7 - 5i

(1) -7
(2) -3
(3) 3
(4) 7

2. Originally Posted by magentarita
Solve for x: (3 + 2i) + (4 + xi)= 7 - 5i

(1) -7
(2) -3
(3) 3
(4) 7
3 + 2i + 4 + xi = 7 + (2 + x)i

now equate real and imaginary parts...

3. Hi magentarita.

Its simple math:

$\displaystyle (3 + 2i) + (4 + xi)= 7 - 5i$

// - 3 // -2i

$\displaystyle 4+x*i = 4 -7i$

//-4

$\displaystyle x*i = -7i$

// : i

=> $\displaystyle x = -7\frac{i}{i} = -7$

Kind regards,
Rapha

4. ## what does......

Originally Posted by Rapha
Hi magentarita.

Its simple math:

$\displaystyle (3 + 2i) + (4 + xi)= 7 - 5i$

// - 3 // -2i

$\displaystyle 4+x*i = 4 -7i$

//-4

$\displaystyle x*i = -7i$

// : i

=> $\displaystyle x = -7\frac{i}{i} = -7$

Kind regards,
Rapha
In this case, what does the symbol // mean?

5. ## ok....

Originally Posted by Jhevon
3 + 2i + 4 + xi = 7 + (2 + x)i

now equate real and imaginary parts...
7 + (2 + x)i = 7 - 5i

7 + 2i + xi = 7 - 5i

7 - 7 + xi = -2i - 5i

xi = -7i

x = -7i/i

x = -7

Is this correct?

6. Originally Posted by magentarita
7 + (2 + x)i = 7 - 5i

7 + 2i + xi = 7 - 5i

7 - 7 + xi = -2i - 5i

xi = -7i

x = -7i/i

x = -7

Is this correct?
Yes, but it's easier to just say

Real parts: $\displaystyle 7 = 7$, correct.

Imaginary parts: $\displaystyle 2 + x = -5 \implies x = -7$.

7. Originally Posted by magentarita
In this case, what does the symbol // mean?
It means nothing.
I just use(d) it to show the steps.
Don't you know some Programming languages (like Java)? Sometimes you use " // " to comment several lines out.

Regards,
Rapha