For this problem,we use the Fundamental Counting Principle. You know that there are 7 digits in a number. In this principle, you have to multiply the possible numbers for every digit. If the first number cannot be zero, then there are 9 possible numbers. So, the value for the first digit is 9. The second digit could be any number but less of 1 because it was used in the 1st digit. So, that would be 10 - 1 = 9. The third digit must be the value in the second digit less than 1. That would be 9 - 1 = 8. And so on and so forth. The solution would be:
9×9×8×7×6×5×4 = 544,320 7-digit numbers
Answer:
3 1/3
Step-by-step explanation:
Answer:
(A) 509.78
We need to move the decimal point after the first non-zero digit
So,
=> 5.0978 × 10² (Since the decimal point is moved two places to the left)
(B) 0.0289
Again after the first non-zero digit:
So, it becomes:
=> 2.89 × 10⁻² (Since the decimal point is moved 2 places to the right so it will be negative also)
Answer:
y=30
x=60
Step-by-step explanation:
The triangle has all sides equal therefore all the angles are equal.
For all the angles to be equal and add up to 180 (sum of angles in a triangle is 180), each angle has to be 60.
Therefore y=90-60
=30
x=180-(30+90)
=60
Set the whole expression = to 0 and solve for x.
3x^(5/3) - 4x^(7/3) = 0. Factor out x^(5/3): x^(5/3) [3 - 4x^(2/3)] = 0
Then either x^(5/3) = 0, or 3 - 4x^(2/3) = 0.
In the latter case, 4x^(2/3) = 3.
To solve this: mult. both sides by x^(-2/3). Then we have
4x^(2/3)x^(-2/3) = 3x^(-2/3), or 4 = 3x^(-2/3). It'd be easier to work with this if we rewrote it as
4 3
--- = --------------------
1 x^(+2/3)
Then
4
--- = x^(-2/3). Then, x^(2/3) = (3/4), and x = (3/4)^(3/2). According to my 3 calculator, that comes out to x = 0.65 (approx.)
Check this result! subst. 0.65 for x in the given equation. Is the equation then true?
My method here was a bit roundabout, and longer than it should have been. Can you think of a more elegant (and shorter) solution?
