1. **Stating the problem:**
We are given the system of equations:
$$\frac{9}{2}x + 4y = 27$$
$$\frac{3}{2}x + 4y = 21$$
We need to find the value of $$\frac{17}{2}x + 6y$$ at the solution point $$(x,y)$$.
2. **Formula and approach:**
To solve for $x$ and $y$, we use the method of elimination or substitution. Since both equations have $4y$, subtracting one from the other will eliminate $y$.
3. **Subtract the second equation from the first:**
$$\left(\frac{9}{2}x + 4y\right) - \left(\frac{3}{2}x + 4y\right) = 27 - 21$$
Simplify:
$$\frac{9}{2}x - \frac{3}{2}x = 6$$
$$\frac{6}{2}x = 6$$
$$3x = 6$$
$$x = 2$$
4. **Substitute $x=2$ into the second equation to find $y$:**
$$\frac{3}{2} \times 2 + 4y = 21$$
$$3 + 4y = 21$$
$$4y = 18$$
$$y = \frac{18}{4} = \frac{9}{2} = 4.5$$
5. **Calculate the required expression:**
$$\frac{17}{2}x + 6y = \frac{17}{2} \times 2 + 6 \times \frac{9}{2}$$
$$= 17 + 6 \times 4.5$$
$$= 17 + 27 = 44$$
6. **Answer:**
The value of $$\frac{17}{2}x + 6y$$ is **44**, which corresponds to option C.
System Equations 3D2892
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