Mary has scored 99, 83, 74, and 69 on her previous four tests. What score does she need on her next test so that her average
1 answer:
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Move all the logarithms on the left hand side, and all the constants on the other:
Use the rule of logarithms
To rewrite the equation as
Evaluate 2 to the power of each side:
Multiply both sides by 2x:
Place the decimal point right after the first nonzero digit, which is 3.
So you'll go from this
to this 
after this move.
Now ask yourself: "how many spots must I move the decimal point to get back to 0.003045?"
The answer is "3 spots to the left"
The exponent of the final answer is -3
The negative indicates "move left" and the 3 tells us how many places to move the decimal
Therefore,
Answer: Choice C)
This is assuming you meant to write the -3 as an exponent
So you'll go from this
Now ask yourself: "how many spots must I move the decimal point to get back to 0.003045?"
The answer is "3 spots to the left"
The exponent of the final answer is -3
The negative indicates "move left" and the 3 tells us how many places to move the decimal
Therefore,
Answer: Choice C)
This is assuming you meant to write the -3 as an exponent