8^(y-3)=2^y
i dont understand?

Question

8^(y-3)=2^y
i dont understand?

campbell_st · Answer

you need both sides of the equation to have the same base... 

the you can equate the powers and solve for y

8 = 2^3

so the equation is 

$$(2^3)^{ y - 3} = 2^y$$

just equate the powers and solve for y

anonymous · Answer

equate them?

anonymous · Answer

Put them into an equation:
3(y-3) = y
Since the base is the same on both sides

anonymous · Answer

Sorry its just not making sense to me. I multiply both sides by 3?

anonymous · Answer

One law of exponents states that 
$$(x^a)^b = x^{ab}$$

8^(y-3) = (2^3)^(y-3) = 2^(3y-9)

anonymous · Answer

ok so after i get 2^3y-9=2^y what do i do from there? sorry math is my worse subject

anonymous · Answer

No problem.
Now since they have the same base, 2. You only need to check the exponents.
3y-9 = y

anonymous · Answer

ohhh that makes sense. so you just drop the base! and i think the answer would be 4.5? thank you:)

anonymous · Answer

Thats correct, well done!

anonymous · Answer

i dont understand either