Answer:
slope is 4/3
a = 9
y = -2
Step-by-step explanation:
The slope can be seen from the blue lines with a deltaX of 6 and a deltaY of 8. The slope is defined as deltaY/deltaX, i.e., 8/6 = 4/3.
Between points (6, 6) and (a, 10), deltaX is a-6 and deltaY is 10-6=4.
So 4/(a-6) = 4/3 must hold. This simplifies to a-6 = 3 so a=9.
The equation of the line is y = (4/3)x + b, where b must be chosen such that (6,6) is on the line. b is also by definition the y coordinate of the y intercept.
6 = (4/3)·6 + b, so b = 6 - 8 = -2.
The equation of the line is y = (4/3)x - 2 and it crosses the y axis at (0, -2).
