I'm probably making a silly mistake or Wolfram Alpha is lying to me.(adsbygoogle = window.adsbygoogle || []).push({});

Question: Find the value of c and d.

[itex]3d=13-2c[/itex]

[itex]\frac{3c+d}{2}=8[/itex]

Rearranged, simplified and multiply each equation by 2:

[tex]6d+4c=26[/tex]

[tex]d+3c=16[/tex]

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

[tex]18d+12c=78[/tex]

[tex]-4d-12c=-64[/tex]

Then add them and find what d is worth:

[tex]14d=14[/tex]

[tex]d=1[/tex]

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

[tex]3(1)+2c=13[/tex]

[tex]3+2(c)=13[/tex]

[tex]c=5[/tex]

[tex]d=1, c=5[/tex]

What am I doing wrong? Sorry if this is the long winded way to do it.

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# Linear equations using addition

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