x=3, you can find this by using finding common bases for equation b because 243=3^5. Because of that you can get rid of three on both sides to get the equation 2x-1=5 and then just solve for x to get x=3. For the first equation 5^3=625 so that also proves x=3.
Sorry if my explanation is a little disorganized if you need more help feel free to ask

subtract the numbers:


subtract 9 from both sides

simplify

divide both sides by 6


decimal
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Hope this helps :)
<h3>
2 Answers: B and D</h3>
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Explanation:
Choice B is one answer because -2 and 2 are additive inverses that add to -2+2 = 0
Choice D is a similar story. We have -5+5 = 0
In general, if x is some number then -x is its additive inverse. So we can say x+(-x) = 0 or -x+x = 0. In short, additive inverses add to 0.
This is a square root meaning whatever number multiplied by itself equals it’s square root. The answer would be 4 on the outside and 3 on the inside