The function of the trapezoid area is:
A(x)=(B+b)*h/2
Where B and b are the bases and h is the height.
With the given data: h=10 B and b =7 and x (it may vary which one is bigger)
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So that function becomes:
A(x)=(7+x)*10/2
A(x)=(7+x)*5
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So if you want the inverse function, you have to operate to find x:
A(x)/5=7+x
A(x)/5-7=x
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So the new function is:
x(A)=A/5-7
I am sorry but this is incomplete. If you would like to PM me the full question I would love to help?
V = x/t = 4.5 mil / 3 h = 1.5 mph
Since, v = 1.5 mph (or we can say that v is constant), distance and time vary directly and the constant of variation is 1.5 mph.