1. **State the problem:** We need to find the expression for $f_1(x) - g_1(x)$ given $f_1(x) = 4 + 0.50x$ and $g_1(x) = 3 + 0.45x$. 2. **Write the subtraction:** $$f_1(x) - g_1(x) = (4 + 0.50x) - (3 + 0.45x)$$ 3. **Distribute the minus sign:** $$= 4 + 0.50x - 3 - 0.45x$$ 4. **Combine like terms:** $$= (4 - 3) + (0.50x - 0.45x) = 1 + 0.05x$$ 5. **Final answer:** $$f_1(x) - g_1(x) = 1 + 0.05x$$ This means the difference between the two functions is a linear function with a constant term 1 and a slope of 0.05.