1. **Problem 1:** Find the standard form of a line through $(-1,-4)$ parallel to the line through $(-2,-5)$ and $(2,7)$.
2. Find the slope of the given line using points $(-2,-5)$ and $(2,7)$:
$$m = \frac{7 - (-5)}{2 - (-2)} = \frac{12}{4} = 3$$
3. Since the new line is parallel, it has the same slope $m=3$.
4. Use point-slope form with point $(-1,-4)$:
$$y - (-4) = 3(x - (-1)) \Rightarrow y + 4 = 3(x + 1)$$
5. Simplify:
$$y + 4 = 3x + 3$$
$$y = 3x + 3 - 4$$
$$y = 3x - 1$$
6. Convert to standard form $Ax + By = C$:
$$y = 3x - 1 \Rightarrow -3x + y = -1$$
Multiply both sides by $-1$ to get positive $x$ coefficient:
$$\cancel{-3}x + y = -1 \Rightarrow 3x - y = 1$$
7. **Problem 2:** Find point-slope form of a line through $(2,-8)$ parallel to $y = -\frac{9}{4}x - \frac{1}{2}$.
8. The slope of given line is $m = -\frac{9}{4}$.
9. Use point-slope form:
$$y - (-8) = -\frac{9}{4}(x - 2) \Rightarrow y + 8 = -\frac{9}{4}(x - 2)$$
10. **Problem 3:** Find slope-intercept form of a line parallel to $4x - 10y = -1$ passing through $(15,13)$.
11. Find slope of given line:
$$4x - 10y = -1 \Rightarrow -10y = -4x - 1 \Rightarrow y = \frac{4}{10}x + \frac{1}{10} = \frac{2}{5}x + \frac{1}{10}$$
Slope $m = \frac{2}{5}$.
12. Use point-slope form with $(15,13)$:
$$y - 13 = \frac{2}{5}(x - 15)$$
13. Simplify to slope-intercept form:
$$y - 13 = \frac{2}{5}x - 6$$
$$y = \frac{2}{5}x - 6 + 13$$
$$y = \frac{2}{5}x + 7$$
Parallel Lines 15E909
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