MathzSolver111

Thanks! 

No problem! Have a good day!

We don't actually want to substitute the $y=31-5x$ into the second equation I think you meant substitute into $y$.  After this we get

$-3x+4(31-5x)=-37$ for the second equation. Distribute to get

$-3x+124-20x=-37$ Combine like terms to get

$-23x+124=-37$ Then we subtract $124$ from both sides resulting in

$-23x=-161$ Divide by $-23$ from both sides to get

$x=7$ Plug this into the first equation resulting in

$5(7)+y=31$ Distribute to get

$35+y=31$ Subtract $35$ from both sides to get

$y=-4$. So our answer is 

$(7,-4)$

So all the possible values of $n$ are $-76,-4,4,76?$

$1.8446744$e$+19$

$46\frac{2776}{10115}.$ Just a lot of simple operations no need to explain.

We can label the traingles as $t$ and the circles as $c$ to get

$5t+3c=21$

$5c+3t=16$

as our system of equations. Since I am kind of sleepy today, I plugged this into Wolfram|Alpha and got

$t=\frac{57}{16}$

$c=\frac{17}{16}$

so, 

$2c=\frac{34}{16}=\frac{17}{8}$.

I found the correct answer. Your answer is wrong but thanks for trying. 

This is the explanation for the real answer :

Since the perimeter is $18$, $b+c=12$. Also, by the Pythagorean Theorem, $c^{2}-b^{2}=6^{2}$. Thus,
                                                             $36=c^{2}-b^{2}=(c-b)(c+b)=12(c-b)$
So $c-b=3$. Adding $b+c=12$ to this, we find $2c=15\Rightarrow c=\boxed{\frac{15}{2}}$.

Thnx for trying but it's wrong.-.

Thanks hectictar! But... I solved this before you doing the same trial and error xD

The answer was correct and the exact explanation for how to solve after I put in $352$ was almost exactly what you said! Thank you a million!