Answer:
c. 4
Step-by-step explanation:
tan (30)/1 = x/7 *cross multiply*
x = 7 (tan(30))
x = 4.04
x = 4
One example is the equation 2x+3x = 5x because the left hand side combines to form the right hand side. This equation is said to be an identity, which is always true for any real number you can think of. For example, if x = 3, then,
2x+3x = 5x
2*3+3*3 = 5*3 ... replace every x with 3
6 + 9 = 15
15 = 15
We end up with a true equation. This will happen regardless of what x value we pick. Therefore, it has infinitely many solutions.
For the first digit of the required 20-digit number, we can have 9 choices for the number, those are the digits 1 to 9. In the second digit of the number, we will only have 8 choices. That is because, we don't want to write a number in the second digit that is similar to the first digit and the third digit.
Similarly, in the third digit's place, we will only have 8 choices because we do not want the digit to be similar to the second digit and the fourth digit. This will go on up until the 19th digit. In the 20th digit, we will also have 9 choices (from 0-9) but we do not want the digit to be similar to the 19th digit.
From the explanation given above, we have the number of ways,
n = 9 x 8^(19 - 1) x 9 = 1.459 x 10^18
<em>ANSWER: 1.459 x 10^18</em>
The answer would be B because I did this equation on a sheet of paper and I did the parentheses first which led me to my final answer B.