Question

Which exponential function goes through the points (1, 8) and (4, 64)?

Answer 1

Two points are given for the function: (1, 8) and (4, 64)
Put x = 1 and see which one gives you 8.
And put x = 4 and see which one gives you 64.
Both points should be satisfied and when you try both points will know which one does.

Answer 2

\[a. f(x)=4(2)^{x}\]\[b. f(x)=2(4)^{x}\]\[c. f(x)=4(2)^{-x}\]\[d. f(x)=2(4)^{-x}\]

Answer 3

Okay...will do.

Answer 4

1 & 16?

Answer 5

That sounds wrong...

Answer 6

Let us take a) f(x) = 4(2)^x
put x = 1
y = 4(2)^1 = 8 So it satisfies (1,8)

put x = 4
y = 4(2)^4 = 4 * 16 = 64. So it satisfies (4,64)

So both points are on the curve and so the first function goes through both points.

Try the other function choices too.

Answer 7

Ah. So it must be A, right? Since it satisfies both points... I'll do the other ones for you.

Answer 8

Yeah it is a). But it would be good to make sure the other functions don't satisfy both points.

Answer 9

\[f(x)=2(4)^{x}\]\[f(1)=2 \times 4\]\[f(1)=2 \times 4\]\[f(1)=8\]

Answer 10

\[f(x)=2(4)^{x}\]\[f(4)=2 \times 4^{4}\]\[f(4)=2 \times 256\]\[f(4) = 512\]

Answer 11

So B satisfies (1, 8), but not (4, 64).

Answer 12

yes. so it is not b.

Answer 13

Nerp.

Answer 14

c) and d) don't even satisfy the first point and so they are out too.

Answer 15

So it's A!

Answer 16

Can you help me on another one? I just need you to check if it is correct. thnx.