# Questions on Algebra: Matrices, determinant, Cramer rule answered by real tutors!

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 Algebra: Matrices, determinant, Cramer rule Solvers Lessons Answers archive Quiz In Depth

 Question 94381: Find the product: ` Find the product: Click here to see answer by Edwin McCravy(8999)

 Question 94333: Given A = 3 -2 0 1 4 2 -1 5 -3 find -3A. Thank you for your help Click here to see answer by jim_thompson5910(28717)

 Question 94709: Find the determinant of the matrix. A=[-2 5] [3 7] Click here to see answer by stanbon(57984)

 Question 94795: x+y=11 Use Cramer's rule to solve the x-y=5 following system of equations. If D=0, use another method to solve the system. Click here to see answer by Edwin McCravy(8999)

 Question 95025: True or False. the following matrices can be multiplied. [2 -2] [0 1] [3 -3] [9 -1] [0 1] Click here to see answer by stanbon(57984)

 Question 95230: please give step by step procedure for finding out solutio of for following matrix using Gauss jordan elimination method with partial pivoting. 3x + 2y - 4z = 3 2x + 3y + 3z = 15 5x - 3y + z = 14 Click here to see answer by samuel nkadi(2)

 Question 97240: 3x+5y+6z=3 2x+3y+5z=1 -2x+7y-34z=-4 use Gauss-Jordan elimination method to find the inverse of the coefficient matrix. Click here to see answer by stanbon(57984)

 Question 98073: Determine value of (k) as an exact decimal so that the system has no solution. 5x-4y=8 6x+ky=11 Click here to see answer by stanbon(57984)

 Question 99425: Solve the matrix (I-A)X=D for the given matrices A,D,and X. [0.1 0.1]=A [0.2 0.1] [7 ]=D [14] [x]=X [y] Please enter each number as a decimal Round each answer to two decimals x= y= Click here to see answer by stanbon(57984)

 Question 100491: heres my question Is solving systems by substitution, elimination or cramers rule which is easiest my teacher said we can use any of the three on an up coming test to solve only for 2 variables i'm not real proficient at any yet. and I want to focus on one skill / formula / to get thru this exam which one can you explain briefly (he can't) I'm frustrated because 1.) he dosent teach it out of the book and goes to quicklyin class to learn. Can you help me with a simple format I can understand THANK YOU jackie Click here to see answer by stanbon(57984)

 Question 100470: During the 2003-2004 NBA season, Dirk Nowitzki of the Dallas Mavericks made a total of 976 shots and scored 1680 points. His shots consisted of 3-point field goals than free throws. Use an inverse matrix to find how many of each type of shot he made. Click here to see answer by stanbon(57984)

 Question 101340: Could you please take the time to help me solve this question: Suppose A is a 2 x 3 matrix, where its first row consists of 1, 2, and 0, and its second row consists of 0, 2, and 1. Find the transpose of A, i.e., AT, then multiply A by its transpose, i.e., A AT and finally find the inverse matrix of their product. Thank you, very much for taking the time to help me, most appreciated Click here to see answer by jim_thompson5910(28717)

 Question 102522: Solve by using the Gauss-Jordan elimination method: x+y-z=2 2x+3y-z=7 3x-2y+z=9 I know that you have to convert them to 1 0 0 | 2 0 1 0 | 7 0 0 1 | 9 I am just not clear on how to do this row by row. Any help would be greatly appreciated. Click here to see answer by jim_thompson5910(28717)

 Question 102566: Use the elimination method to find all solutions of the system; A. 5x+2y=-19 7x+3y=-27 x=___ y=____ b. x+3y=5 6y+z=12 x-2x=10 c. 2/x+3y=16 -1/x+2/y=6 d. y=64-x^2 y=x^2-64 The two solutions of the system are: one with x<0 x=___ y=____ one with x>0 x=___ y=____ I have tried working the elimination rules but am confused with getting rid of x in the second equation to solve for y? Click here to see answer by rmromero(383)

 Question 102575: Please help with the following: Let A= 2 -1 4 3 B= [3 1] Perform the following operations if possible: a. 4BA b. B^2 c. A+2B Am I right in the possiblity that a and c are not possible? Click here to see answer by jim_thompson5910(28717)

 Question 102524: This one is set up like a word problem and I could use some assistance. A company produces both large and small cabinets. A small cabinet requires 1 hour of labor and a large cabinet requires 4 hours of labor. The company has at most 80 hours of labor available each day. No more then 60 small cabinets and no more than 15 large cabinets can be produced in a day due to space limitations. If the company's profit is \$120 per small cabinet and \$250 per large cabinet, how many of each should be produced to maximize profit? What is the maximum profit? Click here to see answer by ankor@dixie-net.com(15747)

 Question 102832: Find the solution of using substitution, elimination or Cramers Rule x^2+y^2=7 x-y^2=-1 Click here to see answer by checkley75(3666)

 Question 102828: Use the matrix equation AX=B to solce the system 3x-2y=6 x-2y=10 I know that you set it up in the system 3 -2 and 6 1 -2 10 Just not sure where to go after that... Click here to see answer by stanbon(57984)

 Question 103781: i want to know the steps of solving it Click here to see answer by elima(1433)

 Question 105146: There were 1500 people at a high school football game. Student tickets were \$2.00 and adult tickets were \$3.50. The total receipts for the game were \$3825. How many students bought tickets? Click here to see answer by doukungfoo(195)

 Question 105148: An airplane flew 4 hours with a 25 mph tail wind. The return trip against the same wind took 5 hours. Find the speed of the airplane in still air. Click here to see answer by ankor@dixie-net.com(15747)

 Question 105250: solve each systme of equation by graphing??/ x is < less then 4 and the next one is y>2 Click here to see answer by elima(1433)

 Question 95450: Prove that the set of all 3 x 3 matrices with real entries of the form [ 1 a b 0 1 c 0 0 1] is a group. (Multiplication is defined by [ 1 a b 0 1 c 0 0 1] x [1 a' b' 0 1 c' 0 0 1] [ 1 (a+a') (b'+ac'+b 0 1 c'+c = 0 0 1 ] this group, sometimes called the Heisenberg group after the Nobel Prize winning physcicist Werner Heisenberg, is intimately related to the Heisenberg Uncertainty Principle of quantum physics. ) PLEASE HELP DUE TODAY Click here to see answer by rahul(6)

 Question 105797: This is a word problem and we have been using cramer's rule, but I don't know how to set it up. Rosa rides the bus to work. Usually she rides 35 min and then walks 6 min to get to work. Since the bus travels at 30 miles per hour and her walking speed is 5 mph, she can easily determine that the total distance is 18 miles. One day when the weather was nice, she decides to get off the bus earlier and walk the rest of the way for exercise. She only has a total of 75 min to get to work, so she can't afford to get off the bus too early. How much time should she spend on the bus before getting off to walk? The answer is 28.2 min. I have been out of school due to medical reasons for over a month and I am trying to teach myself the math before I go back. If you can help me to figure out how to set this up I would really appreciate it. Click here to see answer by stanbon(57984)

 Question 106518: The questions is Find a basis for the span of the given vectors. [1, -1, 0], [-1, 0, 1], [0, 1, -1]. For some reason I reduced it and got [1 0 0], [0 1 0], [-1 -1 0] but i am not sure where/how to go from here and the book that we have does't give an example of how to do this. Was I even supposed to reduce it? Click here to see answer by jim_thompson5910(28717)

 Question 106542: Find a basis for the span of the given vectors [1 -1 0], [-1 0 1], [0 1 -1] I reduced it and got stuck after that. I am supposted to use the properties (zero martrix and such) or something else? I am just stuck and have no clue as to what I am looking for. Our text is custum and does not have an example of this but it does have examples of finding the basis of row space, column space, and null cpace of a matrix. Is this the same thing? Please Help! Thank you in advance!!! Click here to see answer by jim_thompson5910(28717)

 Question 106547: Sorry, last question! Prove that if the columns of A are linearly independent, then they must for a basis for col(A). the only thing that i could think of was to take a matrix and reduce it but you can use an example to prove something (they don't give A and they don't say if it is a 2x2 or a 4x4 or anything). I have no idea where to go from here. Thanks in advance! Click here to see answer by jim_thompson5910(28717)

 Question 106640: Here T defined by .Find a vector “x” whose image under T is b, and determines whether x is unique. A=1 -3 2 0 1 -4 3 -5 -9 b= 6 -7 -9 Click here to see answer by jim_thompson5910(28717)

 Question 107383: hi I'm having a problem solving an augmented matrix if someone could help me that would be great!! The directions are solve the system using an augmented matrix 5x+2y=2 3x-y=-12 Thank-you so much for your help Click here to see answer by jim_thompson5910(28717)