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Tutors Answer Your Questions about Matrices-and-determiminant (FREE)
Question 213861This question is from textbook Algebra 2
: A jeweler plans to combine two silver alloys to make 50 grams of alloy that is 75% silver and contains 37.5 grams of pure silver (75% of 50 grams). If some silver alloy is 80% silver and the other is 60% silver, how many grams of each are needed?This question is from textbook Algebra 2
Click here to see answer by josmiceli(3007)   |
Question 220252: For the following system, write the D,Dx,Dy,and Dz
You would need to use Cramer's Rule.
Then use Crammer's Rule to find the value of z.
-2x-3y-z=5
-x-2y-3z=-3
3x+3y+7z=2
This is what I got: z=dz/d=-18/-7=18/7, z=18/7
I want to know if my answer was correct. Thank you.
Click here to see answer by Alan3354(6079)  |
Question 220864: Ok this one is stumping me.
An outdoor amphitheatre has 25,000 seats. Ticket prices are $15, $17, and $25. The number of tickets priced at $17 must equal two times the number priced at $25. How many tickets should be sold ( assuming all seats can be sold) to bring in $434,500? . Set up a system of equations an dsolve using th inverse matrix method.
I was setting up like this:
X+Y+Z = 25,000
15x + 17y + 25z = 43500
But I cannot get a third set to be able to use the inverse function on my TI84
without it I get the "INVALID DIM" error
HELP!!!!!
Click here to see answer by Alan3354(6079) |
Question 222462: HI. I am having a little trouble with the 3x3 determinants. I have got the 2x2 down just fine. Here is my problem. -5 -3 2 second row 8 0 7 third row 3 2 -6. I know that I have to cancel row 1 and column 1 and solve the 2x2, but then what? Any help is greatly appreciated! Thanks!
Click here to see answer by jim_thompson5910(13787) |
Question 222736: Hi again, just wanted t know if the question I have been asking has something wrong with it, because I havnt received any kind of response to it at all. If not can someone please help me. The following questions are for two seperate hypothetical matrices.
Here they are again:
Suppose MATRIX AB is defined.
a) If A is 4*6 and B is a column matrix, give the dimensions of B and AB.
b) (different matrix) If A is the identity matrix and B is 6*6, what size is A?
Thanks, -Nick.
Click here to see answer by user_dude2008(715) |
Question 223984: wilma wants to have 2,000,000 when she retires in 45 yrs assuming she can average a 4.5%return- how much should she invest now? I got the rule down I believe as p=a(1+I)^n but not sure how to put it together
Click here to see answer by rfer(2688) |
Question 229023: Hi all, I asked this question recently but havnt been given a responce yet. Any help would be greatly appreciated.
I need to Solve the following system of equations by using Gaussian elimination. I also need to include the row operation used next to each row.
2x - y + 3z = 24
2y - z = 14
2x - 5y + 7z = 6
Thanks, -Nick.
Click here to see answer by stanbon(26268) |
Question 229703: solve the system
x+y+z=-1
x-y+3z=-17
2x+y+z=-2
Solve the system
x-y+2z=7
2x+z=4
x+5y+z=9
Solve the system
3x+4y=-2
x=-2y
Solve the system
3x+4y=40
x-2y=0
Solve the system
x-y+z=6
x+y+z=2
x+y-z=0
Solve the system
y-3z=-12
-2x+y+2z=5
2x+3z=7
Click here to see answer by solver91311(5072)  |
Question 230768: Using inverse matrix, solve the following problem:
A high school math department purchased brand A calculators
for $80 each and brand B calculators for $95 each. It purchased
a total of 20 calculators at a total cost of $1780. How many brand A
and brand B calculators did the department purchase?
Click here to see answer by rfer(2688) |
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