Question

I’ve been stuck on this for a while!!!!!

Answer 1

Answer:

See explanation.

Step-by-step explanation:

Part A.

If two curves intersect, they have the same x- and y-coordinates.

So if we set the y-coordinates equal to each other, we are finding for what x-coordinate those y-coordinates will be the same. Therefore solving 2^(-x)=8^(x+4) gives us an x- so that both sides are the same (where both sides represent the corresponding y- coordinate for that x- in the curves given by y=2^(-x) and y=8^(x+4).

Part B.

x      | 2^(-x)                                | 8^(x+4)

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-3      2^(-(-3))=2^3=8                  8^(-3+4)=8^1=8

-2      2^(-(-2))=2^2=4                  8^(-2+4)=8^2=64

-1       2^(-(-1))=2^1=2                    8^(-1+4)=8^3=512

0       2^(-(0))=2^0=1                    8^(0+4)=8^4=4096

1        2^(-(1))=2^(-1)=1/2                8^(1+4)=8^5=32768

2       2^(-(2))=2^(-2)=1/4              8^(2+4)=8^6=262144

3       2^(-(3))=2^(-3)=1/8              8^(3+4)+8^7=2097152

So in the table we see both lists have the same y-coordinate when the x-coordinate is -3.

The solution to equation 2^(-x)=8^(x+4) is therefore x=-3 since the table tells us both sides is the same value, 8, for this x-coordinate.

Part C.

You can graph both curves given by y=2^(-x) and y=8^(x+4) on the same coordinate plane. Where they intersect is the solution.

I use the table in part B to help guide me in plotting the points to help graph the curves for each equation. I have included a visual in an attachment.

They cross at (-3,8) so this is the solution.

So this tells me 2^(-x)=8^(x+4) has solution at x=-3 since both sides will be 8 at that x-.