Question

PLZ Help I will fan and give a medal

Which exponential function goes through the points (1, 16) and (4, 128)?

f(x) = 4(4)x

f(x) = 8(2)x

f(x) = 8(2)-x

f(x) = 4(4)-x

Answer 1

@geekfromthefutur are the "x"s exponents?

Answer 2

Yes

Answer 3

Okay, then this is quite a simple problem let me walk you through it.

The basic equation for exponential graphs are y=ab^x
By plugging in both points into that equation we can solve for a and b respectively.

So we plug in (1,16) into the equation
16 = ab^1

We also plug in (4, 128) into the equation
128 = ab^4

If you multiply 16 by 8 we get 128, so multiply 8 to both sides.

128 = 8ab^1
128 = ab^4

128 = 128

8ab^1 = ab^4
8ab = ab^4

Divide both sides by a
8b = b^4

Divide both sides by b
8 = b^3

Cube root both sides
2 = b

Choose one of the equations we made and plug b in.

16 = ab^1
16 = ab
16 = 2a
a = 8

SO your exponential equation will be y = 8(2)^x

Second answer choice.

:)

Answer 4

Hopefully that made sense, haha

Answer 5

Dang i was wondering what was takin so long bro

Answer 6

Well, I wanted to make sure you understood properly. :p

Answer 7

Yea i do now