Question: A line is drawn through $(-7, 11)$ and $(8, -9)$. The equation
$y - 11 = -\frac{4}{3} (x + 7)$ is written to represent the line. Which
equations also represent the line? Check all that apply.
y = -\frac{4}{3} x + \frac{5}{3}
3y = -4x + 40
4x + y = 21
4x + 3y = 5
-4x + 3y = 17
y - 11 = -\frac{4}{3} (x + 7)
1. **State the problem:** We are given the line equation $$y - 11 = -\frac{4}{3} (x + 7)$$ and need to find which of the given equations represent the same line.
2. **Start by distributing the right side:**
$$y - 11 = -\frac{4}{3} x - \frac{4}{3} \times 7$$
$$y - 11 = -\frac{4}{3} x - \frac{28}{3}$$
3. **Add 11 to both sides to isolate $y$:**
$$y = -\frac{4}{3} x - \frac{28}{3} + 11$$
4. **Convert 11 to thirds to combine:**
$$11 = \frac{33}{3}$$
$$y = -\frac{4}{3} x - \frac{28}{3} + \frac{33}{3}$$
5. **Combine constants:**
$$y = -\frac{4}{3} x + \frac{5}{3}$$
6. **Check each given equation:**
- $y = -\frac{4}{3} x + \frac{5}{3}$ matches exactly.
- $3y = -4x + 40$:
Multiply both sides of our equation by 3:
$$3y = 3 \left(-\frac{4}{3} x + \frac{5}{3}\right) = -4x + 5$$
This does not equal $-4x + 40$, so this is not the same line.
- $4x + y = 21$:
Rewrite our equation as:
$$y = -\frac{4}{3} x + \frac{5}{3}$$
Multiply both sides by 3:
$$3y = -4x + 5$$
Add $4x$ to both sides:
$$4x + 3y = 5$$
This is not $4x + y = 21$, so no.
- $4x + 3y = 5$:
From above, this matches exactly our rearranged equation.
- $-4x + 3y = 17$:
Check if this matches:
Start from $4x + 3y = 5$, multiply both sides by $-1$:
$$-4x - 3y = -5$$
This is not $-4x + 3y = 17$, so no.
**Final answers:**
- $y = -\frac{4}{3} x + \frac{5}{3}$
- $4x + 3y = 5$
These two equations represent the same line.