Solve graphically by the intersection method. Give the solution in interval notation.

5 x minus 3 less than 2 x minus 6
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Part 1
Graph y 1 equals 5 x minus 3 and y 2 equals 2 x minus 6 using the graphing tool.

Part 2
What is the​ solution?

1 answer

To solve the inequality \( 5x - 3 < 2x - 6 \) graphically by using the intersection method, we'll first rearrange the inequality into two equations:

  1. \( y_1 = 5x - 3 \)
  2. \( y_2 = 2x - 6 \)

Next, we should graph these two equations. Here is how you can do it:

Step 1: Identify Points to Graph

  • For \( y_1 = 5x - 3 \):

    • When \( x = 0 \): \( y = -3 \) (Point: (0, -3))
    • When \( x = 1 \): \( y = 2 \) (Point: (1, 2))
    • When \( x = 2 \): \( y = 7 \) (Point: (2, 7))
  • For \( y_2 = 2x - 6 \):

    • When \( x = 0 \): \( y = -6 \) (Point: (0, -6))
    • When \( x = 3 \): \( y = 0 \) (Point: (3, 0))
    • When \( x = 5 \): \( y = 4 \) (Point: (5, 4))

Step 2: Graph the Lines

Using the points above, you can plot the lines on a graph. You would draw a straight line for each equation, \( y_1 \) and \( y_2 \).

Step 3: Find the Intersection

To find the intersection of the two lines \( y_1 = 5x - 3 \) and \( y_2 = 2x - 6 \), set them equal to each other:

\[ 5x - 3 = 2x - 6 \]

Step 4: Solve for \( x \)

Subtract \( 2x \) from both sides:

\[ 5x - 2x - 3 = -6 \] \[ 3x - 3 = -6 \] Add 3 to both sides:

\[ 3x = -3 \] Divide by 3:

\[ x = -1 \]

Step 5: Find the \( y \) value at the Intersection

Now substitute \( x = -1 \) back into either equation to find \( y \):

\[ y = 5(-1) - 3 = -5 - 3 = -8 \]

So the intersection point is \((-1, -8)\).

Step 6: Determine the Range of \( x \) for the Inequality

Since we're looking for \( 5x - 3 < 2x - 6 \), we determine:

  • For \( x < -1 \): \( y_1 \) will be below \( y_2 \).
  • For \( x = -1 \): \( y_1 = y_2 \).
  • For \( x > -1 \): \( y_1 \) will be above \( y_2 \).

Thus, the solution to the inequality \( 5x - 3 < 2x - 6 \) occurs where \( x < -1 \).

Final Solution in Interval Notation

The solution is:

\[ (-\infty, -1) \]