Question

Line MN passes through points M4, 3) and M7, 12). If the equation of the line is written in slope-intercept form, y-mx+ b, what is the value of b?

Answer 1

Answer:

b = -9

Step-by-step explanation:

The slope-intercept form of an equation of a line:

$y=mx+b$

m - slope

b - y-intercept

The formula of a slope:

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

We have the points M(4, 3) and N(7, 12). Substitute:

$m=\dfrac{12-3}{7-4}=\dfrac{9}{3}=3$

Therefore we have the equation:

$y=3x+b$

Put the coordinates of the point M to the equation:

$3=3(4)+b$

$3=12+b$            subtract 12 from both sides

$-9=b$