What # do you need the first five multiples for? and the only factors for 7 are one and seven because it is a prime number!
Hey!
Hope this helps...
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To solve this, we will be doing a semi-alternate route, but it will get us to our answer...
400 / 100 = 4
30 / 4 = 7.5 seconds
60 * 60 * 7.5 = 27,000 meters per hour
<em></em><em>Lets plug it into our meters to miles formula...</em>
27,000 / 1,609.344 ~ 16.777 miles per hour
So...
The answer is: The Polar Express was going 27,000 meters per hour (or roughly close to 16.777 miles per hour)...
Here I copy the steps and indicate where the error is.
Square root of negative 2x plus 1 − 3 = x=> <span>this is the starting equation
</span>
√[ - 2x + 1] - 3 = x
Square root of negative 2x plus 1 − 3 + 3 = x + 3 in this step she added 3 to each side, which is fine
<span> Square root
of negative 2x plus 1 = x + 3 <span>she made the addtions => fine</span></span>
Square root of negative 2x plus 1 − 1 = x + 3 – 1 due to <span>plus 1 in inside the square root, this step will not help</span>
<span> Square root
of negative 2 x = x + 2 <span>wrong! she cannot simplify - 1 that is out of the square root with +1 that is inside the square root
</span></span>
<span>Then, from here on all is wrong, but she made other additional mistakes.</span>
(Square root of negative 2 x)2 = (x − 4)2 −2x <span> the right side should be (x+2)^2 which is x^2 + 4x +4 not (x-4)^2 - 2x</span>
Later she made a mistake changing the sign of -8x to +8x
Those are the mistakes. Finally, the global error is that she should verify whether the found values satisfied the original equation.
