Use the graph and table to write the equation that describes the line graphed.

Question image

Understand the Problem

The question is asking to derive the equation of a line based on the provided graph and corresponding table of values. We will use the points in the table to determine the slope and y-intercept of the line.

Answer

The equation of the line is \( y = x + 3 \).
Answer for screen readers

The equation of the line is ( y = x + 3 ).

Steps to Solve

  1. Identify two points from the table

We can choose two points from the table:

  • Point 1: $(-2, 1)$
  • Point 2: $(0, 3)$
  1. Calculate the slope (m) of the line

The formula for the slope between two points $(x_1, y_1)$ and $(x_2, y_2)$ is:

$$ m = \frac{y_2 - y_1}{x_2 - x_1} $$

Substituting $(x_1, y_1) = (-2, 1)$ and $(x_2, y_2) = (0, 3)$:

$$ m = \frac{3 - 1}{0 - (-2)} = \frac{2}{2} = 1 $$

  1. Use the slope-intercept form

The slope-intercept form of a line is given by the equation:

$$ y = mx + b $$

We have found $m = 1$, so the equation now looks like:

$$ y = 1x + b $$

  1. Determine the y-intercept (b)

To find $b$, we can use one of the points. Using the point $(0, 3)$:

$$ 3 = 1(0) + b \implies b = 3 $$

  1. Write the final equation

Substituting the values of $m$ and $b$ back into the equation:

$$ y = 1x + 3 $$

This simplifies to:

$$ y = x + 3 $$

The equation of the line is ( y = x + 3 ).

More Information

This equation represents a line with a slope of 1, which means that for every 1 unit increase in ( x ), ( y ) increases by 1 unit. The y-intercept at ( (0, 3) ) indicates where the line crosses the y-axis.

Tips

  • Incorrectly identifying points: Make sure to accurately read the coordinates from the table.
  • Mistaking slope calculation: Remember that the slope is the rise over run; be careful with subtraction in the slope formula.
  • Forgetting to substitute properly: Ensure that when you find ( b ), you correctly substitute the point values into the equation.

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