Answer:
B. 1.2 x 
Step-by-step explanation:
Scientific notation is a way of writing very large or very small numbers. A number is written in scientific notation when a number between 1 and 10 is multiplied by a power of 10. For example, 650,000,000 can be written in scientific notation as 6.5 ✕ 10^8. Or, in this case it's the opposite since we have a negative number. Since it's a decimal it's multiplied by 10 still but the exponent is negative. All we need to do to find what the exponent would be in this case is to count the number of zeros before the "12." There are 4 zeros before the 12. So your exponent would be -4. Now all we need to do is write out "equation" per say.
1.2 x 10^-4
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X = the number of humans and y = the number of horses.
x+y=74
2x+4y=196
Because the number of humans and horses together is 74, and the total number of legs (2 per every human, x, and 4 per every horse, y) is 196. Then, just use elimination to solve.

So, now that you have y, you can plug it into the first equation to find x:

So, x = 50 and y = 24, so there are 50 humans and 24 horses.
The correct answer is B.
Answer:
4.5
Step-by-step explanation:
You can change 1/4 to a decimal and then multiply 2×2.25
Use the inverse sine function on a calculator.
arcsin (0.88) = 1.08 radians
The first-serve percentage of a
tennis player in a match is normally distributed with a standard deviation of
4.3%. If a sample of 15 random matches of
the player is taken, the mean
first-serve percentage is found to be 26.4%. The margin of error of the sample
mean is 83.71%.