<span>Work out the Mean (the simple average of the numbers)Then for each number: subtract the Mean and square the result.Then work out the mean of those squared differences.<span>Take the square root of that and we are done!</span></span>
First, fidn the volume of the little cubes that the rectangular prism can hold instide of itself. The formula for volume is length x width x height. This means you have to multiply 1/2 x 1/2 x 1/2. 1/2 x 1/2 x 1/2 = 1/8. Now, since the rectangular prism can hold 840 of these cubes, you need to multiply each cube's volume, 1/8, by 840. 1/8 x 840 = 105.
Your answer should be: 105 ft.^3
Second one is correct, that is an identity.
Third one is a contradiction:
6x - 15 = 3 * (2x - 6) ------> 6x - 15 = 6x - 18
Fourth one:
5x - 3 * (x - 4) = 2 * (x - 6) ---> 5x - 3x + 12 = 2x - 12 ---> 2x + 12 = 2x -12
So this is a contradiction as well.
