Chapter 1: Problem 28
Finding Equations of Lines Find an equation of the line that satisfies the given conditions. Through \((-3,-5) ; \quad\) slope \(-\frac{7}{2}\)
Short Answer
Expert verified
The equation of the line is \(y = -\frac{7}{2}x - \frac{31}{2}\).
Step by step solution
01
Identify the Formula
To find the equation of a line given a slope and a point, we use the point-slope form of a line equation: \[ y - y_1 = m(x - x_1) \]where \((x_1, y_1)\) is a point on the line and \(m\) is the slope.
02
Substitute the Given Values
Substitute the slope \(m = -\frac{7}{2}\) and the point \((-3, -5)\) into the point-slope formula. This gives us:\[ y - (-5) = -\frac{7}{2}(x - (-3)) \]which simplifies to:\[ y + 5 = -\frac{7}{2}(x + 3) \]
03
Distribute the Slope
Distribute the slope \(-\frac{7}{2}\) into the expression \(x + 3\):\[ y + 5 = -\frac{7}{2}x - \frac{7}{2} \times 3 \]Calculating the multiplication, we get:\[ y + 5 = -\frac{7}{2}x - \frac{21}{2} \]
04
Isolate y
To convert into slope-intercept form \(y = mx + b\), subtract 5 from both sides:\[ y = -\frac{7}{2}x - \frac{21}{2} - 5 \]Express 5 as \(\frac{10}{2}\) to match the denominator:\[ y = -\frac{7}{2}x - \frac{21}{2} - \frac{10}{2} \]
05
Simplify
Combine the terms on the right side:\[ y = -\frac{7}{2}x - \frac{31}{2} \]This is the slope-intercept form of the line's equation.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Point-Slope Form
When you're given a point and a slope, the point-slope form is your best friend for finding the equation of a line. This formula allows you to plug in the slope and any point on the line to get started on your equation journey. The formula for the point-slope form is:
- \( y - y_1 = m(x - x_1) \)
- \( m \) stands for the slope of the line.
- The point \((x_1, y_1)\) is any point through which the line passes.
Slope-Intercept Form
Once you have the point-slope form prepared, moving to the slope-intercept form is a straightforward next step. The slope-intercept form of a line equation, \( y = mx + b \), is essential because it highlights two crucial aspects of your line: the slope \( m \) and the y-intercept \( b \). It’s like the final GPS coordinates for a delivery on your way!To convert from point-slope to the slope-intercept form, you start by distributing any terms and then isolating \( y \). Let's look at what happens with our example:
- Distribute the slope into the parentheses: \( y + 5 = -\frac{7}{2}x - \frac{21}{2} \)
- Next, you want to isolate \( y \). We do this by subtracting any terms over to the right side: \( y = -\frac{7}{2}x - \frac{31}{2} \)
Mathematical Problem Solving
Things become easier when we approach them methodically, and that's what mathematical problem solving is all about. Tackling line equations involves a series of steps that, once mastered, can make finding solutions a rewarding experience. Here’s how we do it:
- Firstly, identify what information is given and what you need to find. Are you given a point and a slope? Great! Then point-slope form is the way to start.
- Use structured, step-by-step methods like substituting values into formulas accurately. Double-check your values as you plug them in.
- Simplify step by step. Distribute terms, collect like terms, and keep your equations neat.
- Convert between different forms of the line equations as needed. Switching between forms like point-slope and slope-intercept helps in different scenarios.
- Practice makes perfect! The more problems you solve, the more intuitive the process becomes.