Chapter 2: Problem 103
(a) find the intercepts of the graph of each equation and (b) graph the equation. $$ 7 x+2 y=21 $$
Short Answer
Expert verified
Intercepts: (3, 0) and (0, 10.5)
Step by step solution
01
- Find the x-intercept
To find the x-intercept, set y to 0 and solve for x. Start with the equation: \[ 7x + 2y = 21 \]Set \( y = 0 \): \[ 7x + 2(0) = 21 \]Simplify: \[ 7x = 21 \]Divide both sides by 7: \[ x = 3 \]So, the x-intercept is (3, 0).
02
- Find the y-intercept
To find the y-intercept, set x to 0 and solve for y. Start with the equation: \[ 7x + 2y = 21 \]Set \( x = 0 \): \[ 7(0) + 2y = 21 \]Simplify: \[ 2y = 21 \]Divide both sides by 2: \[ y = 10.5 \]So, the y-intercept is (0, 10.5).
03
- Plot the intercepts on the graph
Plot the points (3, 0) and (0, 10.5) on the coordinate plane.
04
- Draw the line
Using the two intercepts, draw a straight line through both points. This line represents the equation \( 7x + 2y = 21 \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
intercepts
Intercepts are crucial points on a graph where a line crosses the axes. They help us understand the behavior of an equation easily. The two main intercepts are:
- The x-intercept, where the line crosses the x-axis.
- The y-intercept, where the line crosses the y-axis.
graphing equations
Graphing equations is an excellent visual method to interpret linear equations. It helps convert the abstract mathematical concepts into clear, visual insights. Here's how you do it:
Additionally, the slope and intercepts can provide many insights, such as predicting values and understanding trends. The equation \[ 7x + 2y = 21 \] is effectively visualized on a graph by connecting these intercept points.
- Step 1: Identify the intercepts - the points where the graph crosses the axes. For our example, the intercepts are (3, 0) and (0, 10.5).
- Step 2: Plot these intercepts on the coordinate plane. Place point (3,0) on the x-axis and point (0,10.5) on the y-axis.
- Step 3: Draw a straight line through the plotted points. This line represents the equation.
Additionally, the slope and intercepts can provide many insights, such as predicting values and understanding trends. The equation \[ 7x + 2y = 21 \] is effectively visualized on a graph by connecting these intercept points.
solving linear equations
Solving linear equations involves finding the values of variables that satisfy the equation. The general form of a linear equation is \[\text{ax} + \text{by} = \text{c}\]. Here's how to solve the given linear equation step-by-step: \[ 7x + 2y = 21 \]
- Start by solving for one variable in terms of the other. For example, solve for y when x = 0 to find the y-intercept.
- Substitute these values back into the equation to solve for the other variable when one variable is set to zero.
- Use these solutions to interpret the equation's behavior graphically.