Tutors Answer Your Questions about Quadratic Equations (FREE)
Question 128015: I am having such a time understanding how to solve...
w^4 - 20w^2 - 2 = 0.
It is not qudratic but is to be reduced to a quadratic equation in order for us to solve it. It is said to be reducible to quadratic.
I know we have to substitute u for w^2. So then the equation would be
u^2 - 20u - 2 = 0
Solving for u is...
u = 10 - radical sign 102 and
u = 10 + radical sign 102
I know the solutions are:
10 - radical sign 102 all under the same radical sign ,
10 + radical sign under radical sign 102 all under the same radical sign ,
10 - radical sign under radical sign 102 all under the same negative radical sign ,
10 + radical sign under radical sign 102 all under the same negative radical sign
My question is: Where did they get 10 and 102? I guess I do not know how to solve for u.
Can You please show the steps for this problem?
This does not come from a book.
Thank you!
Click here to see answer by solver91311(16885)   |
Question 128065: A car purchased in 1998 is currently valued at $12000. If it has decreased in value exponentially at a rate of 4% per year, determine the original cost of the vechicle.
I do know that the formula I should use is A=Ao(1-r)^t or some variation of it but I do not know how to fill it in ???????
Click here to see answer by mr.barrett(5) |
Question 128055: Kate wants her $9000 GIC to double in value in nine years. What annual rate of interest is required for her to reach her goal. Assume interest is compounded annually.
Can this be done without using natural logs and just using "logs" OR are both of these the same thing ?????????????
Click here to see answer by scott8148(6628)  |
Question 128294: At an airshow, a plane is in a power dive. The height of the plane, in metres above the ground , is recorded for the first six seconds.
Time(s): 1,2,3,4,5,6
Height(m): 214,180,150,124,102,84
a) Algebraically determine the quadratic function that models the path followed by the plane. Express the function in the form y=ax^2+bx+c.
b) Use the function to determine the minimum height of the plane.
Click here to see answer by stanbon(57342) |
Question 128327: I dont understand what we have to do for this problem.
Working alone, Anton can install a brick patio in 2 hours less than Bill. Together Anton and Bill can install the patio in 4 hours. To the nearest tenth of an hour, how long does it take Bill to install the patio working alone?
Click here to see answer by josmiceli(9675)  |
Question 128327: I dont understand what we have to do for this problem.
Working alone, Anton can install a brick patio in 2 hours less than Bill. Together Anton and Bill can install the patio in 4 hours. To the nearest tenth of an hour, how long does it take Bill to install the patio working alone?
Click here to see answer by stanbon(57342) |
Question 128438: John and Paul agree to share the work in mowing a rectangular lawn. John agrees to mow half the lawn measuring 30m by 40m by mowing strips of uniform width around the perimeter. Paul agrees to mow the small remaining rectangle when John is finished. How wide a strip should John mow to ensure they share the work equally???
Click here to see answer by ankor@dixie-net.com(15650)  |
Question 128516: Hello
I am have difficulty trying to work this one out, your assistance would be greatly appreciated. Ta.
I am asked to solve 6(3X-4)^2-7(3X-2)-5=0 using the quadratic equation.
The following is what I have tried
6(3X-4)^2-7(3X-2)-5=0
then becomes
6(3X-4)(3X-4)-21X+14-5=0
then becomes
(18X-24)(3X-4)-21X+9=0
then becomes
54X^2-72X-72X+96-21X+9=0
then becomes
54X^2-165X+105=0
This is as far as I could go, and have come to the conclusion that it cannot be done. Can you please confirm this for me, and show me the whys and hows, with an explanation please. Thank you. Cheers D.
Click here to see answer by checkley71(8403) |
Question 128802: Michael purchases a rare coin for $100 that will double in value every 9 years. His friend John purchases a rare book for $75 that will double in value every 6 years. If both purchases were made at the same time, in how many years will they be of equal value??? Please HELP me :)
Click here to see answer by stanbon(57342) |
Question 128813: In a right triangle , the shorter leg is 6 less than the longer leg. The hypotenuse is 6 less than twice the shorter leg. Set up a quadratic equation and use it to determine the lenghth of the hypotenuse of the right triangle.
Click here to see answer by checkley71(8403) |
Question 128813: In a right triangle , the shorter leg is 6 less than the longer leg. The hypotenuse is 6 less than twice the shorter leg. Set up a quadratic equation and use it to determine the lenghth of the hypotenuse of the right triangle.
Click here to see answer by edjones(7569)  |
Question 128844: Hi
I am stuck on this one which has me completely bamboozled. Your assistance would be greatly appreciated.
I am asked to Sol;ve the following equation for the variable given, and to write my answer with 3 significant figures.
The equation is as follows:
2y/5=3/5+2/y
So far this is as far as I have been able to go and I started like this.
2y/5=3/5+2/y
Then
2y/5=2/y+3/5
Then
2y/5-2/y-3/5=0
But I now do not know where to go from here. I have looked at the general quadratic equation ax^2+bx+c=0, but cannot work out which is the a, b or c. Again I have also looked at the x=-b+or-sqrt b^2-4ac/2a, but cannot see where to find the a, b or c.
Your help would really be appreciated. Thank you.
Cheers D.
Click here to see answer by solver91311(16885) |
Question 128844: Hi
I am stuck on this one which has me completely bamboozled. Your assistance would be greatly appreciated.
I am asked to Sol;ve the following equation for the variable given, and to write my answer with 3 significant figures.
The equation is as follows:
2y/5=3/5+2/y
So far this is as far as I have been able to go and I started like this.
2y/5=3/5+2/y
Then
2y/5=2/y+3/5
Then
2y/5-2/y-3/5=0
But I now do not know where to go from here. I have looked at the general quadratic equation ax^2+bx+c=0, but cannot work out which is the a, b or c. Again I have also looked at the x=-b+or-sqrt b^2-4ac/2a, but cannot see where to find the a, b or c.
Your help would really be appreciated. Thank you.
Cheers D.
Click here to see answer by stanbon(57342) |
Question 129057: I am in 9th grade and taking Algebra 1. We are now learning to solve quadratic equations by graphing them. I just don't understand. For example, if they say graph quadratic einequalities and shade the solution region how do I do that? It's confusing.
y ≥ x2 (x squared)
y > -2x2 (x squared)
y ≥ x2 – 2x + 1 (x squared)
Click here to see answer by ilana(307) |
Question 129060: The manager of an 80 unit apartment complex is trying to deceide what rent to charge. Experience has shown that at a rent of $200.00 all the units will be full but with one additional unit will remain vacant f0r each $20.00increase. Find the # of occupied unit if the total revenue is $20,020.
This is the problem I am trying to solve, however I am not clear on how or where to start it. If you could possibly show me the steps I would greatly appericate it. Thank you
Click here to see answer by solver91311(16885) |
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