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if the graph of an exponential function passes through the points (1,6) and (4,48) find an equation of the function

User Avi Avidan
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2 Answers

3 votes
When you write an equation of a line, you first have to find the slope. The equation for slope is (y∨2 - y∨1) / (x∨2 - x∨1), so fill that in with your coordinates.

(48 - 6) / (4 - 1) Subtract your two sets.
42 / 3 Divide
14

So, you know the slope of the equation is 14. Now, you fill in the point-slope equation, (y - y∨1) = m(x - x∨1). Fill it in with one set of coordinates and solve.

(y - 6) = 14(x - 1) Distributive Property
y - 6 = 14x - 14 Add 6 to both sides.
y = 14x - 8
User PCasagrande
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8.2k points
1 vote
one way is trial and error
equation of exonential is
y=a(b^x)
lets try some stuff
one way is trial and error
after 20 minutes we come up with y=3(2^x)

another way is recognizing that this is a sequence

a_(n)=a_(1)r^(n-1)
a1=6, cool
sub
a4=48

48=a_(4)=6r^(4-1)

48=6r^(3)
dividie everybody by 6

8=r^(3)
cube root
2=r

therefor

equation is
f(x)=3(2^x) or y=3(2^x)
User Christoph Haefner
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6.7k points