• Mar 20th 2013, 05:48 PM
uperkurk
I'm probably making a silly mistake or Wolfram Alpha is lying to me.

Question: Find the value of c and d.

$3d=13-2c$
$\frac{3c+d}{2}=8$

Rearranged, simplified and multiply each equation by 2:

$6d+4c=26$
$d+3c=16$

Now find the common multiple which in my case I will use 12:

$18d+12c=78$
$-4d-12c=-64$

Then add them and find what d is worth:

$14d=14$

$d=1$

Now when I plug this back into the equation, I will use the first one:

$3(1)+2c=13$
$3+2(c)=13$
$c=5$

$d=1, c=5$

What am I doing wrong? Sorry if this is the long winded way to do it.
• Mar 20th 2013, 06:18 PM
Shakarri