Write an exponential function in the form y=ab^x whose graph passes through the given points: (2,48),(5,750)
Ok, so the function form is y = a * bx.
Substitute in the values:
750 = a * b5
and
48 = a * b2
Then divide the two equations:
750/ 48 = (a * b5) / (a * b2)
So:
15.625 = b3
Take the cube root of both sides:
2.5 = b
Now, substitue b into one of the equations (the one with 48 has smaller numbers and is easier to work with.)
48 = a * 2.52
Simplify.
48 = a * 6.25
Divide both sides by 6.25
7.68 = a
Now substitute in a and b to write the exponential function:
y = 7.68 * 2.5x
Ok, so the function form is y = a * bx.
Substitute in the values:
750 = a * b5
and
48 = a * b2
Then divide the two equations:
750/ 48 = (a * b5) / (a * b2)
So:
15.625 = b3
Take the cube root of both sides:
2.5 = b
Now, substitue b into one of the equations (the one with 48 has smaller numbers and is easier to work with.)
48 = a * 2.52
Simplify.
48 = a * 6.25
Divide both sides by 6.25
7.68 = a
Now substitute in a and b to write the exponential function:
y = 7.68 * 2.5x
Using the first equation we can "solve" for "a'
48/b^2 = "a" (A)
And substituting this for "a" into the second equation, we get...
750 = (48/b^2)b^5 Divide both sides by 48 and simplify the exponents
750/48 = b^3 .....take the cube root of both sides....
"b"= 2.5
And using (A) and substituting in for "b," we have
48/(2.5)^2 = "a" = 7.68
So....our equation is
y = 7.68(2.5)^x
Check and make sure it works....I'll think you'll find that it will.......
Sorry, kitty<3.....didn't know you were posting, too!!
I'll give you the credit with a "Thumbs Up" and a green check!!