Answer:
9 + 10 +x= 21
x=21-19
x=2
add 2 in left hand side to get 21
The expression equivalent to 4^-5 • 3^-5 is 12^-5
<h3>What are equivalent expressions?</h3>
Equivalent expressions are simply known as expressions with the same solution but different arrangement.
Given the index expressions;
4^-5 • 3^-5
Using the exponent rule, the two values are have different bases but the same exponent and thus, we multiply the bases and leave the exponents the same way.
This can be written as;
4(3) ^ -5
expand the bracket
12^-5
Thus, the expression equivalent to 4^-5 • 3^-5 is 12^-5
Learn more about equivalent expressions here:
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Because 21 is more than 1
A unit multiplier is a conversion factor of value 1 that we can use to convert quantities.
We want to convert 123 pounds per mile to ounces per centimeter.
First, we are going to express the quantity to convert as a fraction:
123 pounds per mile=

Next, we are going to find our multipliers:
- We know for our problem that there are 5,280 feet in 1 mile, so our first multiplier will be:

- We also know that there are 16 ounces in 1 pound, so our second multiplier will be:

- We know that there are 12 inches in 1 foot, so our third multiplier will be:

- We know that t<span>here are approximately 2.54 cm in 1 inch, so our fourth multiplier will be: </span>

Now we can put all our multipliers together:

We can conclude that the answer is
0.01