Difference means subtraction, so the difference between 12 <u>times a number</u> is known as 12x because we do not know what is being multiplied by 12. Same with 9 times a number. Since 12 and 9 have two numbers that we don't know the value of, we have to change one of them to a different variable because we do not know if it is the same number or not. So it would be 12x-9y, or any letters you choose.
Answer: The equation would be 59.50 = 30 + .25x. You would solve by subtracting 30 from 59.50, and you get 29.5. Then dividing .25 by that, and you get 118. So you sent 118 texts. i think this is the answer good luck :D
When angles are restricted to real numbers, Bernhard is correct. The sine function has a range of -1 to 1 (inclusive).
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When angles are allowed to be complex numbers, the magnitude of the sine of an angle may exceed 1. In this realm, both Henrik and Bernhard are incorrect.