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Darren is finding the equation in the form [tex]y = mx + b[/tex] for a trend line that passes through the points [tex](2, 18)[/tex] and [tex](-3, 8)[/tex]. Which value should he use as [tex]b[/tex] in his equation?

A. \(-34\)
B. \(-19\)
C. \(2\)
D. [tex]\(14\)[/tex]


Sagot :

To find the equation of a line in the slope-intercept form \( y = mx + b \) that passes through the points \((2, 18)\) and \((-3, 8)\), we need to follow these steps:

1. Calculate the slope \(m\):
The slope \(m\) of the line passing through two points \((x_1, y_1)\) and \((x_2, y_2)\) is given by the formula:
[tex]\[ m = \frac{y_2 - y_1}{x_2 - x_1} \][/tex]
Substituting the given points \((2, 18)\) and \((-3, 8)\):
[tex]\[ m = \frac{8 - 18}{-3 - 2} = \frac{-10}{-5} = 2 \][/tex]

2. Use one of the points to find the y-intercept \(b\):
We can use the point \((x_1, y_1)\) and the slope to find the y-intercept \(b\) using the equation:
[tex]\[ y = mx + b \][/tex]
Rearrange this to solve for \(b\):
[tex]\[ b = y - mx \][/tex]
Use the point \((2, 18)\) and the slope \(m = 2\):
[tex]\[ b = 18 - 2 \cdot 2 = 18 - 4 = 14 \][/tex]

Therefore, the value Darren should use as [tex]\(b\)[/tex] in his equation is [tex]\( \boxed{14} \)[/tex].