Answer:
D

Explanation:
We are given that three vertices of a trapezoid are A(3,-3), B(12,6) and C(4,8).
We have to find the equation of line CD.
Slope formula :

Slope of AB=

AB is a base of trapezoid.
In trapezoid , one pair of sides are parallel.
In given trapezoid , CD is parallel to AB.
When two lines are parallel then, slopes of lines are equal.
Therefore , slope of CD=1
The equation of line with slope 1 and passing through the point C (4,8) is given by
Substitute the values then we get
The equation of line with slope 1 and passing through the point C (4,8) is given by


The equation of line with slope 1 and passing through the point C (4,8) is given by

Answer:D
