Answer:
-3
Explanation:
An increase in x-value from 9 to 10 is an increase of 1 unit. The slope of -7 tells you that the corresponding change in y will by -7 units:
v = 4 -7 = -3
The value of v is -3.
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Alternate solutions
You can see this easily on a graph, or you can use the equation of the line. We have a point and a slope, so the point-slope form is useful.
y = m(x -h) +k
y = -7(x -9) +4
For x=10, the value of y is ...
v = -7(10 -9) +4 = -7 +4
v = -3