Answer:
y is 10
Explanation:
first take your imformation and put it into the y intercept from.
Which is y=mx+b
so take the cordinates (5,2) and put it into the y-intercept form.
the 5 is x and the 2 is the y, so
2=m*5+b
Then take the slope of -3 and put it in the y-intecept from
2=-3*5+b
then solve for b
2=-3*5+b
2=-15+b
+15 on both sides
17=b
now you know the equation of the line is
y=-3x+17
now plug in your x to find the y of that cordinate
on the line.
y=-3*9+17
solve
y=-3*9+17
y=-27+17
y=10