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x + y - 2z = 5
2x + 3y + 4z = 2
So far, I have placed each of the numbers into an augmented matrix. I do not know how to proceed from here. 1 solutions
Answer 131855 by solver91311(16897) on 2009-01-14 22:58:15 (Show Source):
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Linear-equations/176742: I am a bit overwhelmed by the complexity of this question. Please help me to understand and answer the question.
If matrix A is transformed into matrix B by means of an elementary row operation, is there an elementary row operation that transforms B into A? 1 solutions
Answer 131842 by solver91311(16897) on 2009-01-14 22:19:10 (Show Source):
You can put this solution on YOUR website!There are three elementary row operations:
1. Switching the position of two rows. Obviously, you can just switch them back again.
2. Multiplying each element of a row by a non-zero constant. Just multiply that row by the reciprocal of the non-zero constant.
3. Replacing a row with the sum of that row and a multiple of another row. Just subtract the multiple again.
So, the answer to your question is yes.
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Probability-and-statistics/176732: Can someone double check my work please.
Two dice are rolled. Find the probability that the score on the dice is 8?
8 = (1,7)(6,2)(4,4)(3,5)(5,3)(4,4)(2,6)(7,1)
8/36 = 2/9 1 solutions
Answer 131808 by solver91311(16897) on 2009-01-14 20:04:55 (Show Source):
You can put this solution on YOUR website!First of all, how did you get (1, 7) or (7, 1)? DO NOT take that pair of dice to Vegas -- you might get your thumbs broken by some big casino security goon. Second of all, you counted (4,4) twice. Nope, (4,4) is a single outcome. So there are 8 = (6,2) or (5,3) or (4,4) or (3,5) or (2,6) = 5 ways to make an 8 and the probability of rolling 8 is  .
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Probability-and-statistics/176735: Can someone double check my work please.
Two dice are rolled. Find the odds that the score on the dice is either 6 or 12?
6 = (1,5)(2,4)(3,3)(3,3)(4,2)(5,1) = 6/36 = 1/6
12 = (6,6)(6,6) = 2/36 = 1/18
Did I do this right? 1 solutions
Answer 131802 by solver91311(16897) on 2009-01-14 19:58:20 (Show Source):
You can put this solution on YOUR website!Not quite.
There are 5 ways to make a 6: (1, 5), (2, 4), (3, 3), (4, 2), and (5, 1). There is 1 way to make a 12: (6, 6).
There are a total of 36 different results: 6 ways one die can come up times 6 ways the other die can come up.
Since you want the probability of rolling a 6 OR a 12, then you have a total of 6 different successes (5 ways to make 6 plus 1 way to make 12) out of 36 possible outcomes, so:
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Points-lines-and-rays/176733: Can someone double check my work please.
Find the equation of the line passing through the two points.(2,9)and (0,6)
slope = (y^2 - y1)(x^2 - x1)
slope = (6 + 9)(0 + 2)
slope = 15/2
Did I do this right? 1 solutions
Answer 131798 by solver91311(16897) on 2009-01-14 19:52:51 (Show Source):
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Equations/176729: Maggie makes a $9.25 purchase at a bookstore in Reno with a $20 bill. The store has no bills and gives her the change in quarters and fifty-cent pieces. There are 30 coins in all. How many of each kind are there?
please help me! thank you!! 1 solutions
Answer 131795 by solver91311(16897) on 2009-01-14 19:45:56 (Show Source):
You can put this solution on YOUR website!The number of quarters:
The number of 50c pieces:
Given:
The value of each quarter is 25 cents, so the value of all her quarters is  in cents.
Similarly the value of all her 50c pieces is
The total value of her change is  dollars which is the same as  cents. The value of the quarters plus the value of the 50c pieces must equal the total value of the change, so:
Solve the first equation for  :  →  .
Substitute this expression for  into the second equation:
Solve for
So there were 13 half-dollars, and therefore  quarters.
Check:
 Checks.
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real-numbers/176727: A train traveled m miles at a speed of s mph. A bus following the same route traveled 5 mph slower. How much longer did the bus take than the train to make this trip? Write the answer as a single rational expression. 1 solutions
Answer 131792 by solver91311(16897) on 2009-01-14 19:30:18 (Show Source):
You can put this solution on YOUR website!Use distance = rate times time.  . Here,  and  is the speed of the train.  is the speed of the bus.
Since  ,  and...
for the train:
for the bus:
To find out how much longer the bus took, subtract the train's time from the bus' time:
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Rational-functions/176712: How do u solve this problem.
Given: f(x)= x + 2 and g(x) = x^2 + 2
Problem: f(g(1))
how do i do this?? 1 solutions
Answer 131791 by solver91311(16897) on 2009-01-14 19:18:18 (Show Source):
You can put this solution on YOUR website!For x in g(x) substitute 1 and do the arithmetic. Take this value for g(1) and substitute for x in f(x) and do the arithmetic.
Alternatively, though I think it is a bit more work, you could substitute the expression for g(x) for the x in f(x) giving you an expression for (f◦g)(x). Then you can substitute 1 for x in the derived expression.
In general, given a function f defined by f(x) = [some expression in x], you evaluate f(a) by substituting a for x in the expression. It doesn't matter whether a is a number, some other variable, or another function definition or composite of functions.
Remember that f or g or h or some other letter is a function, f(x) or g(x) etc. is the value of the function at x. f(a), then, is the value of the function at a. Typically, things like f(x) are used to describe the general rule for the specific function whereas f(a) is used to examine the value of a particular function at a specific point, namely a.
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Numbers_Word_Problems/176685: 15 more than the square of a number is 8 times the number 1 solutions
Answer 131788 by solver91311(16897) on 2009-01-14 18:44:33 (Show Source):
You can put this solution on YOUR website!Although you don't specifically say, I assume that you want to determine the number.
The number:
The square of the number:
15 more than the square of the number:
8 times the number:
15 more than the square of the number is (=) 8 times the number:
Put the quadratic into standard form and solve by factoring:
Hint: -3 + (-5) = -8 and -3 X -5 = 15
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Functions/176696: evaluate f(x)=3x - 8 for {-2,3,6}. Which set of numbers is the domain and which set of numbers is the range?
1 solutions
Answer 131781 by solver91311(16897) on 2009-01-14 18:34:12 (Show Source):
You can put this solution on YOUR website!Substitute each of the values in the set for x in the function and then do the arithmetic. The values in the given set are elements of the domain and the values in your set of results are elements in the range.
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Graphs/176707: This question is from textbook Elementary and Intermediate Algebra
Slope-Intercept Form
Write an equation for each line. Use slope-intercept form if
possible.
8. Points are (0, 3) and (2, -1)
10. Points are (0, -1) and (4, 1) 1 solutions
Answer 131779 by solver91311(16897) on 2009-01-14 18:31:45 (Show Source):
You can put this solution on YOUR website!Given two points, ) and ) , you can write the equation of the line using the two-point form of the equation of a line:
 . Just insert the values from the two ordered pairs and do the arithmetic.
Once you have simplified things, solve the equation for y (that is, manipulate the equation so that y is by itself on the left and everything else is on the right) to put the equation in slope-intercept form.
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Numbers_Word_Problems/176693: Farmer Billy Bob has 210m of fencing to enclose his pig pen on all 4 sides. What dimensions should his pig pen be to enclose the largest possible area? 1 solutions
Answer 131766 by solver91311(16897) on 2009-01-14 18:14:12 (Show Source):
You can put this solution on YOUR website!The area of a rectangle is given by the length times the width, and the perimeter is given by 2 times the length plus 2 times the width:
 and
We want to maximize  subject to the constraint that  .
 →  , so solve for either  or  .
 →
Now substitute this expression for  into the Area function:
 →
Now we have a second degree polynomial with a negative lead coefficient, so the graph is a concave down parabola. The vertex of a concave down parabola is a maximum, so we need to find the value of the W coordinate for the vertex. The vertex of a parabola expressed in  has an x-coordinate of  . In this problem we have  and  , so the W-coordinate is at  . Hence, for the maximum area, the width must be 52.5 meters.
So if  and  ,  and the pig pen needs to be a square 52.5 meters on each side.
As you may expect, it is true in general that a rectangle with maximum area for a given perimeter is a square. For extra credit, prove it.
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Rational-functions/176666: This question is from textbook McDougal Littell Algebra 2
How do you multiply and divide rational expressions? 1 solutions
Answer 131756 by solver91311(16897) on 2009-01-14 17:15:40 (Show Source):
You can put this solution on YOUR website!Just like any other fractions.
 regardless of whether a, b, c, and/or d are numbers or polynomial expressions. Of course, the  result may need to be reduced to lowest terms.
Likewise  . Again, the  result may need to be reduced to lowest terms.
Lastly, you must exclude values of a variable that would cause any denominator to equal zero. For example:
 is undefined for
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Polynomials-and-rational-expressions/176682: The length of a rectangular swimming pool is 2x-1m + the width is x+2 meters. Write a polynomial A(z represents the area) Could somebody please help me do this problem? I have tried and do no know how to do it. Thanks in advance. Judy 1 solutions
Answer 131753 by solver91311(16897) on 2009-01-14 17:04:36 (Show Source):
You can put this solution on YOUR website!The area of a rectangle is the length multiplied times the width. So just say:
Then use FOIL to multiply the binomials to obtain the desired polynomial expression.
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Systems-of-equations/176631: Ramon mixes 12 liters of 8% acid solution with a 20% acid solution, which results in a 60% acid solution. Find the number of liters of 20% acid solution in the new mixture. 1 solutions
Answer 131703 by solver91311(16897) on 2009-01-14 12:28:20 (Show Source):
You can put this solution on YOUR website!The stated result is impossible. The mixture solution must be a smaller concentration than at least one of the constituents. Now if you meant "...12 liters of 80% acid..." you would have a solvable problem. Write back with the correct problem statement.
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