1. **Problem statement:** Solve the first system of equations and find the value of $x+y$.
2. **Write the equations:**
$$2x+3y=7$$
$$x-y=1$$
3. **Use the second equation to express one variable:**
From $x-y=1$, we get
$$x=1+y$$
4. **Substitute into the first equation:**
$$2(1+y)+3y=7$$
$$2+2y+3y=7$$
$$2+5y=7$$
5. **Solve for $y$:**
$$5y=7-2$$
$$5y=5$$
$$\cancel{5}y=\cancel{5}$$
$$y=1$$
6. **Find $x$:**
$$x=1+y=1+1=2$$
7. **Compute $x+y$:**
$$x+y=2+1=3$$
8. **Final answer:**
$$\boxed{3}$$
Solve System C20C9D
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