1. **State the problem:** We are given the equation $x + y = z$ and values $x=4$, $y=7$, and $z=47$. We need to check if the equation is true with these values. 2. **Substitute the values into the equation:** Replace $x$ with 4, $y$ with 7, and $z$ with 47 in the equation: $$4 + 7 = 47$$ 3. **Simplify the left side:** $$4 + 7 = 11$$ 4. **Compare both sides:** The left side is 11 and the right side is 47. 5. **Conclusion:** Since $11 \neq 47$, the equation $x + y = z$ is **not true** when $x=4$, $y=7$, and $z=47$. 6. **Summary:** The expression $x + y$ equals 11 when $x=4$ and $y=7$. The left and right sides of the equation are not equal after substitution, so the equation is false.