Line MN passes through points M(4, 3) and N(7, 12). If the equation of the line is written in slope-intercept form, y = mx + b, what is the value of b?

–15
–9
3
9

User Icon for Bot GPT 4-o mini Bot GPT 4-o mini answered
3 hours ago

To find the value of \( b \) in the slope-intercept form of the equation of the line \( y = mx + b \), we need to first calculate the slope \( m \) of the line that passes through points \( M(4, 3) \) and \( N(7, 12) \).

The formula for the slope \( m \) between two points \( (x_1, y_1) \) and \( (x_2, y_2) \) is given by:

\[ m = \frac{y_2 - y_1}{x_2 - x_1} \]

Substituting in the coordinates of points \( M \) and \( N \):

  • \( (x_1, y_1) = (4, 3) \)
  • \( (x_2, y_2) = (7, 12) \)

Now, plug in the values:

\[ m = \frac{12 - 3}{7 - 4} = \frac{9}{3} = 3 \]

Now that we have the slope \( m = 3 \), we can use the point-slope form of the equation to find \( b \). We can plug one of the points into the slope-intercept form. Let's use point \( M(4, 3) \).

We substitute \( m = 3 \), \( x = 4 \), and \( y = 3 \) into the equation \( y = mx + b \):

\[ 3 = 3(4) + b \]

This simplifies to:

\[ 3 = 12 + b \]

To solve for \( b \):

\[ b = 3 - 12 = -9 \]

Therefore, the value of \( b \) is

\[ \boxed{-9} \]