1. **State the problem:** Determine whether $x$ and $y$ show direct variation, inverse variation, or neither for equations 4 to 11.
2. **Recall definitions:**
- Direct variation: $y = kx$ for some constant $k$.
- Inverse variation: $xy = k$ or $y = \frac{k}{x}$ for some constant $k$.
- Neither: relationship does not fit either form.
3. **Analyze each equation:**
**4.** $y = 5x$
- This is exactly $y = kx$ with $k=5$, so direct variation.
**5.** $y = \frac{7}{x}$
- This is $y = \frac{k}{x}$ with $k=7$, so inverse variation.
**6.** $xy = -4$
- Matches $xy = k$ with $k=-4$, inverse variation.
**7.** $y = x^2$
- Not linear in $x$, so neither.
**8.** $y = 3x + 2$
- Has an added constant, not pure $y = kx$, so neither.
**9.** $x = \frac{1}{y}$
- Rearranged: $xy = 1$, inverse variation.
**10.** $y = -2x$
- Matches $y = kx$ with $k=-2$, direct variation.
**11.** $y = 4$
- Constant $y$, no $x$ dependence, neither.
4. **Final answers:**
- 4: direct variation
- 5: inverse variation
- 6: inverse variation
- 7: neither
- 8: neither
- 9: inverse variation
- 10: direct variation
- 11: neither
Variation Types 764Bfa
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