Which expressions record the product of exactly two factors ?
2 answers:
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Answer:
A
Step-by-step explanation:
In order to compare all three numbers, you must change them all to have the same form, either all decimal form, all fraction, or all percentages.
The easiest ways to compare are decimal and percentage, as they're practically the same thing. For simplicities sake, though, let's turn all the numbers into decimal.
Since 0.85 is already in decimal form, leave it as it is.
3/4 can be turned into a decimal by putting it into a calculator, but intuitively you should know that it's 0.75. If you don't know a fraction intuitively, you just need to make the fraction into a multiple of denominator 100 and take the numerator. For example:
Numerator is 75.0, now simply move the decimal place up to to get the decimal form 0.75.
91% can be changed into a decimal by moving the decimal place left 2 places. 91.0% turns into 0.91.
Now that you can see the numbers, just rearrange them from least to greatest
0.75<0.85<0.91
equal to A
Try this solution:
Answer: 6 & 4.5 (m-per-h)
Step-by-step explanation:
- The basic formula used in this task is S=V*t, where S - distance, V - speed, t - time.
- the downstream speed is: V+Vc, where V - the speed of the boat in still water, Vc - the speed of the current.
- the upstream speed is: V-Vc.
- according to the described above the distance for downstream is S1=(V+Vc)*t1, where t1=10; the distance for upstream is S2=(V-Vc)*t2, where t2=70.
- for whole travel down- and upstream: S=S1+S2.
- Using these it is possible to make up the system of the equations:
V - the speed of the boat in still water - 6 miles per hour, Vc - the speed of the current - 4.5 miles per hour. All the details for the system of the equations are in the attachment.
Answer:
x < -3 or x > 4
Step-by-step explanation:
The product of the factors is 4th-degree, and the leading coefficient is 1 (positive).
The factors tell you the following about the zeros:
x = -3 . . . sign change from + to -
x = -1 . . . graph touches, but no sign change. - on either side of x=-1
x = 4 . . . sign change from - to +
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The function will be positive for x < -3 and for x > +4.
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<em>Additional comments</em>
The value of the function is zero when any of its factors is zero. The value of a factor changes sign when the value of x changes from one side of the 0 to the other. For example, here, we have x+1 as a factor, so x=-1 is a zero. When x = -0.9, the factor is positive (-0.9 +1 = 0.1). When x = -1.1, the factor is negative (-1.1 +1 = -0.1). If this factor were to the first power, it would cause the value of the function to change sign at x=-1.
However, the factor (x+1) has an even power: (x+1)^2. That means when the factor is negative, its square is positive, and when the factor is positive, its square is positive. In short, the factor (x+1)^2 causes the function to be zero at x=-1, but does not make the function change sign there.
The product of all of these factors will result in a polynomial with x^4 as the highest-degree term. That means the function is of even degree. The leading coefficient is 1, so is positive, and the function will generally have a U-shape. The left-most (odd-degree) zero will be where the function changes sign from positive to negative. The right-most (odd-degree) zero will be where the function changes sign from negative to positive. Those zeros are x=-3 and x=+4, respectively. There are no places between these where the function changes sign, so these zeros are the ends of the regions where the function is positive (>0).
