Question

If the coordinates of point A are (8, 0) and the coordinates of point B are (3, 7), the y-intercept of AB is _____.

. If the coordinates of point D are (5, 5), the equation of line is y =

x + __.

Answer 1

1. The line passing through AB is given by

$\dfrac{x-x_A}{x_B-x_A}=\dfrac{y-y_A}{y_B-y_A}$

Plugging the values, we have

$\dfrac{x-8}{3-8}=\dfrac{y-0}{7-0} \iff \dfrac{x-8}{-5}=\dfrac{y}{7}$

Multiply both sides by 35 to get

$-7x+56=5y \iff y=-\dfrac{7}{5}x+\dfrac{56}{5}$

The y intercept of this line is 56/5.

2. We don't know who point D is.