Let
x -----> the thing you are in control
y -----> the result of that thing
we ahve the ordered pairs
(3,40) and (6,61)
I will assume that is a linear relationship between x and y
so
Step 1
Find the slope or unit rate
the formula to calculate the slope between two points is equal to
m=(y2-y1)/(x2-x1)
we have
(x1,y1)=(3,40)
(x2,y2)=(6,61)
substitute in the formula
m=(61-40)/(6-3)
m=21/3
m=7
step 2
Find the equation of the linear equation
we know that'the equation of a line in point slope form is equal to
y-y1=m(x-x1)
we have
m=7
(x1,y1)=(3,40)
substitute
y-40=7(x-3)
y-40=7x-21
y=7x-21+40
y=7x+19
Remember that
the variable x is the input
the variable y is the output
so
The question is what’s the output of 72
so
For x=72
substitute in the equation
y=7(72)+19
y=523
The output is 523