How do you solve this??? I need it fast please help with steps. (x+3)(x+1)^2(x−4)>0
1 answer:
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).
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So, in order to solve this problem, I will set up an equation. First, let's make x= the # of hours it takes Mr. Itol to complete a computer task, and since his assistant takes twice as long, lets make 2x=the # of hours it takes the assistant to complete the task. We also know that it takes the two of them 6 hours to complete the task together. We can now set up the following equation:
Now, in order to be able to solve this, we have to find the least common denominator, and then we can cancel out the denominators to solve for the top part. The LCD=6x and the new equation becomes:
Now, we can get rid of the denominators, and we get:
So, x= 9
Now we know that Mr. Itol would take 9 hours to complete the task if he were to do it himself. To find how long it would take his assistant to complete the same task by himself, we just need to plug in the x-value into 2x:
Therefore, your answer is that Mr. Itol would take 9 hours to do the job alone, while his assistant will take 18 hours (double the time) to do the job alone.
Hope this helps :)
Now, in order to be able to solve this, we have to find the least common denominator, and then we can cancel out the denominators to solve for the top part. The LCD=6x and the new equation becomes:
Now, we can get rid of the denominators, and we get:
So, x= 9
Now we know that Mr. Itol would take 9 hours to complete the task if he were to do it himself. To find how long it would take his assistant to complete the same task by himself, we just need to plug in the x-value into 2x:
Therefore, your answer is that Mr. Itol would take 9 hours to do the job alone, while his assistant will take 18 hours (double the time) to do the job alone.
Hope this helps :)