Answer: 
Step-by-step explanation:
Given
Points are 
Convert mixed numeral to fraction

Slope of the line is

Equation of line

So, when x = -10.
If you notice, -10 is NOT in the domain (the domain is (-3,13))
so, there is no solution.
You question isn't clear, but I assume that you are asking for the slop of a line parallel to y=-(5/4)(x)+7.
The line parallel would have a slop of -5/7 and the line perpendicular would have a slop of 5/7.
The difference between the two answers is the sign of the two slopes, one is positive the other is negative
To find the value of f(3) we need to follow the below steps :
Step 1 : First plot the graph of f(x)
Step 2 : We need to find f(3) or the function value at x = 3 therefore, in the graph locate the point (3,0)
Step 3 : Draw a line parallel to Y-axis passing through the point (3,0) .
Step 4 : Now there exists two cases :
If the drawn line do not intersect the graph of f(x), then no value of f(3) exists for the given function of x
If the drawn line intersects the graph, then the intersection point is marked and a line parallel to x - axis is drawn passing through that marked or intersection point. And the line where it intersects the y - axis is our required value of f(3).
If this is wrong than I guess I wasn't smart enough :)
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