Equation of a straight line passing through point A parallel to side BC; A (11; 6) B (0; 6) C (-5; -6).

To begin with, let’s form the equation of the line BC. We have two points: B (0; 6) and C (-5; -6). Substitute the coordinate values into the equation of the straight line y = k * x + b:

6 = 0 * k + b;

-6 = -5 * k + b;

b = 6;

-6 = -5 * k + 6;

-5 * k = -12;

k = 2.4.

Hence, the equation of the line BC has the form:

y = 2.4 * x + 6.

Lines are parallel if their slopes k are equal:

k2 = k1 = 2.4.

The straight line looks like:

y = 2.4 * x + b. Substitute the coordinates of point A and form the equation of the straight line:

6 = 11 * 2.4 + b;

b = 6-26.4;

b = -20.4.

The equation is:

y = 2.4 * x – 20.4.