Question

AB and BC form a right angle at their point of intersection, B. If the coordinates of A and B are (14, -1) and (2, 1), respectively, the y-intercept of AB is ____ and the equation of BC is y = __ x + __ . If the y-coordinate of point C is 13, its x-coordinate is ___

Answer 1

1) BC intercept y at (2,1) (given)

2) The slope of AB ===> m= (-1 - 1)?(14 - 2) ===> m = - 1/6

2) the slope of BC that is perpendicular to AB is the inverse of (1/6) & change the sign, that is 6. To find the function y, apply the formula:
y-y1) = m(x-x1) ===> y-1 = 6(x-2) [the coordinate of B] ==> y= 12x - 11

3) if y= 13, replace y by 13 in the equation:
13 = 12x -11 ===>x  = 2