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Quadratic_Equations/400026: We are studying Equations, Inequalities, and mathematical modeling. Question says to find ALL solutions of the equation. check your solution in original equation. I need help working this problem. Can you show me step-by-etep how to work and solve equation? equation: 6x^4-14x^2=0 1 solutions
Answer 283244 by solver91311(16897) on 2011-01-26 11:57:24 (Show Source):
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Expressions-with-variables/400011: Could someone please explain how to do these problems, we are solving problems with two variables and I do not understand how to even start working on them, the directions state...Solve by the addition-or-subtraction method, if someone could explain how they are solved I think I could get it....
3x-y=-5
2x+2y=-6
I would greatly appreciate it...thanks!!!! 1 solutions
Answer 283240 by solver91311(16897) on 2011-01-26 11:39:36 (Show Source):
You can put this solution on YOUR website!
Step 1: Determine a factor that will transform one of the coefficients on one of the variables into the additive inverse of the coefficient on that same variable in the other equation.
For your example, note that multiplying the first equation by 2 would make the coefficient on in the first equation be -2 which is the additive inverse of 2, the coefficient on in the second equation.
is the first equation after multiplying it by 2.
is the original second equation.
Step 2: Add the two equations, term-by-term to get:
Did you notice how the contrivance to have the coefficients on be additive inverses caused the variable to disappear altogether?
Step 3: Solve for the remaining variable:
Step 4: Substitute the value of the variable you just determined back into either of the original equations:
Step 5: Solve:
Step 6: Specify the solution set:
The solution set consists of a single element, namely the ordered pair
Now that you are done with your example problem, a few general notes.
1. Sometimes you will have to find two multipliers, one for each equation in order to achieve the additive inverse relationship between coefficients in the two equations. For example:
would require multiplication of the first equation by 3 and the second by 5 in order to eliminate the variable.
2. Cross out any reference to "addition-or-subtraction" method. Completely erase such a notion from your head. It is the Elimination method because the purpose of the method is to eliminate one of the variables.
3. While you are at it, eliminate the notions of "subtraction" and "division." You never have to do either. Always add. That is to say perform instead of . You will make orders of magnitude fewer sign errors if you do that. As for division, you multiply by the reciprocal instead. For example, the process instead of will save you lots of grief when you start working with rational functions later on.
4. You will encounter situations where the result of the elimination process will be a triviality, generally , or an absurdity, that is something that looks like .
Every two-variable linear equation has a graph that is a straight line. For any given pair of equations there are three possibilities. One, they can be two lines that intersect in a single point. Such is the case with your example problem -- the solution set consists of a single ordered pair representing the single point of intersection of the graphs of the two lines. Two, they could be exactly the same line, such that any ordered pair that satisfies one of the equations also satisfies the other equation. Graphically, this is represented by the two equations having exactly the same graph, and this situation is indicated by arriving at the trivial result mentioned above. Three, they could be two different but parallel lines. They never intersect, and hence the solution set is the empty set. Such a situation is indicated by achiving an absurd result to the Elimination method.
John

My calculator said it, I believe it, that settles it
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Rational-functions/399727: Attempting to solve what looks like a simple problem, but keep coming up with the incorrect answer.
5/4z - 3/8z
The problem is written as a fraction, with one term directly above the other. I've done the best I can to represent this here.
I came up with 2/4z, which I simplify to 2z. Can you help? 1 solutions
Answer 283051 by solver91311(16897) on 2011-01-25 19:23:46 (Show Source):
You can put this solution on YOUR website!
Presuming you mean:
rather than
which is an equally valid interpretation of what you wrote, proceed as follows:
Find the LCD of 4 and 8. Both 4 and 8 divide 8 evenly, so 8 is the LCD.
Convert . You have to multiply the denominator by 2 to get from 4 to 8, so you have to multiply the numerator by 2 as well. Result:
Now you can add the numerators. 10 plus -3 is 7, so:
Now, for where I think you may have gone wrong. You added 5 and -3 to get 2 and then simply ignored the fact that you had a different denominator in the second fraction. Then, having erroneously decided that the sum was , you changed into 2.
Let's see if your arithmetic makes any sense. I have one whole pizza and a quarter of a pizza. The whole pizza is sliced into 8 slices, and the quarter pizza is two slices. I give you the whole thing and tell you to eat what you want and calculate what you have when you are done. You eat 3 of the slices and then, according to your arithmetic, you have 2 whole pizzas left. I never believed that loaves and fishes story either.
John

My calculator said it, I believe it, that settles it
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Linear-systems/399731: I don't understand how to make a word problem into a linear system. This is an example in my Algebra I book:
You are planning a party for a friend. You can have the party at a pizza place for $8 per person plus $30 for favors and a small cake, or at a taco place for $12 dollars per person plus $14 for a large cake.
Could you please create a linear system from this data? 1 solutions
Answer 283043 by solver91311(16897) on 2011-01-25 19:05:12 (Show Source):
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Mixture_Word_Problems/399624: two-fifths of the area of school parking lot can be used for a cultural festival. if the whole parking lot is 7800 square feet, how many square feet can be used for the festival? 1 solutions
Answer 282974 by solver91311(16897) on 2011-01-25 16:50:17 (Show Source):
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Mixture_Word_Problems/399622: sandra spent 2/5 of an hour helping a customer extange an unwanted gift. then she spent 1/2 an hour giving a costumer a refund. what fraction of an hour did she spend helping both customer? 1 solutions
Answer 282972 by solver91311(16897) on 2011-01-25 16:48:04 (Show Source):
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Quadratic_Equations/399586: f(x) = −2x^2− 4x + 15 please do step by step so i can understand
1.Express the quadratic function in standard form. how did you get the numbers
F(x)=
2.vertex (x, y) = how did you get the numbers
3.x-intercepts (x, y) = Small value)
4.(x, y) = larger value)
5.y-intercept (x, y) =
graph and where do the numbers meet???
Thank you soo much... 1 solutions
Answer 282964 by solver91311(16897) on 2011-01-25 16:24:41 (Show Source):
You can put this solution on YOUR website!
Standard form is:
Where is the vertex.
Complete the square. Factor the lead coefficient from the terms with variables:
Divide the coefficient on the first degree term by 2, square the result, and add that result INSIDE the parentheses. Compensate by adding the opposite of what you inserted inside the parentheses multiplied by the lead coefficient.
2 divided by 2 is 1, 1 squared is 1, add 1 inside the parentheses. -2 times 1 is -2, the opposite of -2 is 2, add 2 to the end.
Factor the trinomial inside the parentheses and collect terms:
Paying careful attention to the signs, by inspection, the vertex is at
The -intercepts are the points where the graph of the function crosses the -axis. The -coordinates of the -intercepts are those values of that make the value of the function equal zero. Set the function equal to zero and solve.
So the -intercepts are and
The -intercept is the value of the function when is zero.
So the -intercept is
Don't know what you mean by "where do the numbers meet" The Quadratic Club, or maybe at the Math Court at the Mall? I give up.
John

My calculator said it, I believe it, that settles it
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Permutations/399184: 1-in how many ways can a committee of 3 be selected from a class of 8 students?
1 solutions
Answer 282689 by solver91311(16897) on 2011-01-24 20:12:06 (Show Source):
You can put this solution on YOUR website!
It depends. Is it a committee of 3 equals, such that a committee consisting of Alice, Bill, and Julia is exactly the same as Julia, Alice, and Bill? Or is the order in which the people are specified significant?
If it is the first way (order doesn't matter) then you need the number of combinations of 8 things taken 3 at a time.
The number of combinations of things taken at a time, , is calculated by
On the other hand, if order matters, then you need the number of permutations of 8 things taken 3 at a time. The calculation is very similar except that you remove one factor from the denominator, namely the number of ways you can arrange things. Hence:
Happy arithmetic.
John

My calculator said it, I believe it, that settles it
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Polynomials-and-rational-expressions/399163: i need to solve this problem through factoring and not sure how to goa bout setting it up.
A llama farmer buys a roll of fence that measures 600 feet in length. FInd the dimensions of the rectangular are the fence can enclose if it contains 19475 square feet.
I know l X w = area 1 solutions
Answer 282679 by solver91311(16897) on 2011-01-24 20:01:40 (Show Source):
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