Recall that the equation of a straight line given the gradient(slope), "m" and Y- intercept "c" is given as
y = mx + c
Thus, for question 1, m = -9 and c = 2
We have that
y = -9x + 2
For question 2,
m = 4.5 and c = -10
Thus the equation of the straight line will be
y = 4.5x + (-10)
y = 4.5x - 10
OR