Chapter 2: Problem 49
Find the intercepts. Then graph by using the intercepts, if possible, and a third point as a check. $$ x+y=4 $$
Short Answer
Expert verified
The intercepts are (4,0) and (0,4). The third point is (2,2).
Step by step solution
01
Identify x-intercept
To find the x-intercept, set y to 0 in the equation \(x + y = 4\) and solve for x.
02
Solve for x
Substitute \(y = 0\) into the equation: \(x + 0 = 4\). Thus, \(x = 4\). The x-intercept is \((4,0)\).
03
Identify y-intercept
To find the y-intercept, set x to 0 in the equation \(x + y = 4\) and solve for y.
04
Solve for y
Substitute \(x = 0\) into the equation: \(0 + y = 4\). Thus, \(y = 4\). The y-intercept is \((0,4)\).
05
Choose a third point
Select another value for x, for example, \(x = 2\), and solve for y.
06
Solve for y with x = 2
Substitute \(x = 2\) into the equation: \(2 + y = 4\). Solving for y gives \(y = 2\). The third point is \((2,2)\).
07
Graph the points
Plot the x-intercept \((4,0)\), the y-intercept \((0,4)\), and the third point \((2,2)\) on the coordinate plane. Draw a straight line through these three points to graph the equation.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
x-intercept
The x-intercept is where a graph crosses the x-axis. This means the value of y at this point is 0. To find the x-intercept of an equation, you need to set y equal to 0 and solve for x.
For the equation given, let's find the x-intercept of the equation \(x + y = 4\).
For the equation given, let's find the x-intercept of the equation \(x + y = 4\).
- Set y = 0 in the equation: \(x + 0 = 4\).
- This simplifies to \(x = 4\).
- Therefore, the x-intercept is (4, 0).
y-intercept
The y-intercept is where a graph crosses the y-axis. This means the value of x at this point is 0. To find the y-intercept of an equation, you need to set x equal to 0 and solve for y.
Let's find the y-intercept of the equation \(x + y = 4\).
Let's find the y-intercept of the equation \(x + y = 4\).
- Set x = 0 in the equation: \(0 + y = 4\).
- This simplifies to \(y = 4\).
- Therefore, the y-intercept is (0, 4).
graphing linear equations
Graphing a linear equation helps you see the relationship between the variables. To graph linear equations efficiently, follow these steps:
1. **Find the intercepts**:
2. **Choose a third point**:
3. **Plot the points**:
4. **Draw the line**:
Following these steps will help you graph linear equations quickly and accurately. The intercepts are crucial as they give the easiest points where the line crosses the axes.
1. **Find the intercepts**:
- Find the x-intercept by setting y = 0 and solving for x. For the equation \(x + y = 4\), the x-intercept is (4, 0).
- Find the y-intercept by setting x = 0 and solving for y. For the same equation, the y-intercept is (0, 4).
2. **Choose a third point**:
- Select a different x value and solve for y. For example, if x = 2, then \(2 + y = 4\) simplifies to y = 2. So, (2, 2) is your third point.
3. **Plot the points**:
- Plot the x-intercept (4, 0), the y-intercept (0, 4), and the additional point (2, 2) on the graph paper.
4. **Draw the line**:
- Use a ruler to draw a straight line through these points. This line represents the linear equation \(x + y = 4\).
Following these steps will help you graph linear equations quickly and accurately. The intercepts are crucial as they give the easiest points where the line crosses the axes.