Write the standard form of the equation of the line through the given points: (-2, -5) and (-1, 4)

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Understand the Problem

The question is asking for the standard form of the equation of a line that passes through two given points, (-2, -5) and (-1, 4). To solve it, we need to calculate the slope using the points, then use the point-slope form to derive the standard form of the equation.

Answer

The standard form of the equation is \( 9x - y = -13 \).
Answer for screen readers

The standard form of the equation of the line is ( 9x - y = -13 ).

Steps to Solve

  1. Calculate the slope (m)

To find the slope $m$, use the formula: $$ m = \frac{y_2 - y_1}{x_2 - x_1} $$

Using the points $(-2, -5)$ and $(-1, 4)$:

  • Let $(x_1, y_1) = (-2, -5)$ and $(x_2, y_2) = (-1, 4)$
  • Substitute the values into the formula:

$$ m = \frac{4 - (-5)}{-1 - (-2)} = \frac{4 + 5}{-1 + 2} = \frac{9}{1} = 9 $$

  1. Use point-slope form of the equation

Now use the point-slope form (y - y_1 = m(x - x_1)) with one of the points. We'll use $(-2, -5)$: $$ y - (-5) = 9(x - (-2)) $$

This simplifies to: $$ y + 5 = 9(x + 2) $$

  1. Distribute and rearrange to standard form

Distributing gives: $$ y + 5 = 9x + 18 $$

Now, subtract 9x from both sides: $$ -9x + y + 5 = 18 $$

Subtract 5 from both sides: $$ -9x + y = 13 $$

To write it in standard form Ax + By = C, we want A to be positive, so multiply the entire equation by -1: $$ 9x - y = -13 $$

  1. Write the final standard form

The final standard form of the equation is: $$ 9x - y = -13 $$

The standard form of the equation of the line is ( 9x - y = -13 ).

More Information

The standard form of a linear equation is generally written as ( Ax + By = C ), where A, B, and C are integers. In this case, the slope of the line is 9, indicating a steep incline as the line moves from left to right.

Tips

  • Forgetting the signs when calculating the slope, leading to incorrect values.
  • Misapplying the point-slope formula can lead to mistakes; make sure to carefully plug in the values.
  • Not rearranging the equation to standard form correctly.

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