Question:
Brooke found the equation of the line passing through the points (-7, 25) and (-4, 13) in slope-intercept form as follows.
[tex]Step\ 1: m = \frac{13 - 25}{-4 - (-7)} = \frac{-12}{3} = -4.[/tex]
Step 2:
[tex]y = -4x + b[/tex]
[tex]25 = -4 (-7) + b[/tex]
[tex]25 = 28 + b[/tex]
[tex]25 - 28 = 28 + b -28[/tex]
[tex]b = -3[/tex]
Step 3:
[tex]y = -3x - 4[/tex]
Answer:
She mixed up the slope and y-intercept when she wrote the equation in step 3
Step-by-step explanation:
Given
The steps to determine an equation
Required
Determine the mistake in Brooke's step
Up to the end of step 2, Brooke's step was correct.
Her mistake was in writing the equation.
The form of an equation is;
[tex]y = mx + b[/tex]
Where
[tex]m = slope[/tex]
[tex]m = -4[/tex] ---- in step 1
[tex]b = y-intercept[/tex]
[tex]b = -3[/tex] ---- in step 2
Substitute values for m and b in [tex]y = mx + b[/tex]
[tex]y = -4x - 3[/tex]
Hence:
Option 4 answers the question
