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

Tutors Answer Your Questions about Matrices-and-determiminant (FREE)

Question 65310: can you help me solve for x and y
[3 4y] = [ 3 2]
5 8 2x-1 8

i tried and i got this,
3+4y=3
-4 -4
3y=-1
- -
3 3

y=-1/3
Click here to see answer by venugopalramana(3286)

Question 64106: Use Gaussian elimination with backward substitution to solve the system of linear equations. Write the solution as an ordered pair or ordered triple, whenever possible.
x+2y+z=3
x+y-z=3
-x-2y+z=-5
Click here to see answer by venugopalramana(3286)

Question 64639: find an equation in the form y=ax^2+bx+c whose graph passes through the points (-1,-2), (1,4), (2,13)
Click here to see answer by venugopalramana(3286)

Question 65872: I need help with Matrix and the directions in the book say "Find the product. If it is not defined, state the reason.
The matrix is [7.3 1.5
1.8 0 [-4.2 2.6 -8.7]
2.9 3.2]
Click here to see answer by Edwin McCravy(20054)

Question 66250:
Solve the linear system using the given inverse of the coefficent matrix. w + 6x + 3y - 3z = 2 2w + 7x + y + 2z = 5 w + 5x + 3y - 3z = 3 - 6x - 2y + 3z = 6 A^-1 = Do I plug in the number from the inverse coefficent matrix into the linear system, and then possibly use Cramer's Rule?

Click here to see answer by Edwin McCravy(20054)

Question 67773: PLEASE HELP ME ANSWER THIS QUESTION,I'M GOING TO TAKE A TEST ON THURSDAY ON PROBLEMS SIMILAR TO THIS ONE AND I DON'T GET IT!!!
CONSIDER THE SYSTEM OF EQUATIONS.
9X+3Y+Z=10
25X+5Y+Z=36
4X-2Y+Z=15
a) REWRITE THIS SYSTEM AS A MATRIX EQUATION.

Click here to see answer by stanbon(75887)

Question 68380: 5(x+2)-4(x+3)=10
Click here to see answer by checkley71(8403)

Question 69216:
(x 3)=2(x 2) solve for x (4 x)= (1 3) on each side of the equals sign is one matrix not two separate matices.

Click here to see answer by Edwin McCravy(20054)

Question 69829: Can u please check & tell me if my answer is wrong or not?
Given: C= (matrix(2,2,-3,4,2,5))
B= (matrix(3,2,3,-6,5,7,-4,6))
Question: 3CB
What i've tried: 3(matrix(2,2,-3,4,2,5))* (matrix(3,2,3,-6,5,7,-4,6))

consider them as 4 vertically aligned matrix symbols:
= 3[-3 4]*[3 -6 5]
[2 5] [7 -4 6]
= 3[ (-3*3+4*7) (-3*-6+4*-4) (-3*5+4*6) ]
[ (2*3+5*7) (2*-6+5*-4) (2*5+5*6) ]
= 3 [ (-9+28) (18-16) (-15+24) ]
[ (6+35) (-12-20) (10+30) ]
= 3 [19 2 8]
[41 -32 40]
= [ 3*19 3*2 3*8 ]
[ 3*41 3*-32 3*40]
= [57 6 24]
[123 -96 120]
Final result- (matrix(3,2,57,6,24,123,-96,120))

Click here to see answer by venugopalramana(3286)

Question 70442: Hello. I have just started a new math class, and the teacher is very hard to understand. When someone asks him a question, he thinks they are making fun of his accent. I am trying to a few things out but cannot. He gives us sample problems and does not even go out of a book. The problem directions are Find
A-1 and check your answer. The problem is
A= (1 -2 3)
(-1 0 2)
(4 1 5)
Could someone show me the formula for this problem, and perhaps lead me through it? I am lost and do not want to drop this class. Thanks in advance.
Click here to see answer by venugopalramana(3286)

Question 73000: I'm in an algebra two class and I don't understand one bit of it. When I do finally comprehend, my teacher confuses me. Help! He gave us homework to do and the whole class has decided to omit it. I don't want to. I need to understand this stuff. So can someone please help me? It's due monday. I just need an example so I can try to figure out how to do the rest. Here's the problem...
Calculate the determinant of the matrix.
[18 5]
9 -4
Click here to see answer by stanbon(75887)

Question 73062: (4 -3) (1 -3,-2 8)multiplying matrix
Click here to see answer by jiantess(1)

Question 73109: I don't know if I am on the right track or not , and I am not sure how to finish.
2 [1 -9] [0 -2 -8] - [1 10 6]
[4 3] [4 7 5] - [5 -2 0] The brackets are to go around both rows
(It is 2 times a 2by2 times a 2by3 subtract a 2by3
I have
2[-36 -65 -53] - [1 10 6]
[ 12 13 -17] - [5 -2 0] I am not sure how to do the rest, do I multiply 2 by each # in the first 2x3? Please help.
Click here to see answer by stanbon(75887)

Question 73110: Hi! I am having trouble with writing determinants and understanding Cramer's Rule. Please help me! This is one of my practice questions. There are a few like this so I am hoping if you show me how to do this one, I will be able to do the rest of them myself. Thanks!
Cramer's Rule is used to solve the system of equations:
3x-y+2z=17, 4x+2y-3z=10, and 2x+5y-9z=-6.
Write a determinant to represent the numerator for z.
Click here to see answer by stanbon(75887)

Question 73134: can you also help me solve this system using Cramer's rule?...
s + p + c = 40
c = 4p
s = p - 2
Click here to see answer by bucky(2189)

Question 73125: can you help me write this system as a matrix equation and solve using an inverse matrix please?...
s + p + c = 40
c = 4p
s = p - 2
Click here to see answer by stanbon(75887)

Question 73181: Solve by either elimination, substitution or Crammer's Rule.
I am not sure how to do this problem since there is more than one # on the right side of the =. Please help.
y=10-2z-x
4x-y=2
-5+5z=4x+3y
Click here to see answer by stanbon(75887)

Question 73188: Help! I don't know if I'm doing this right.
Use the matrix method.
x+y-z = -9
2x-y-2z=-3
x+2y+3z=14
I'm confused I seen one way adding R1+R3 to start and another saying interchange row 1 and 3????? This is what I have done:
R1 1 1 -1 | -9
R2 2 -1 -2 | -3
R3 1 2 3 | 14
R1 1 2 3 | 14
R2 2 -1 -2 | -3
R3 1 1 -1 | -9
R1 1 2 3 | 14
R2 0 -5 -8 |-31
R3 1 1 -1 | -9
R1 1 2 3 | 14
R2 0 -5 -8 |-31
R3 0 -1 -4 |-23
R1 1 2 3 | 14
R2 0 1 8/5 | 31/5
R3 0 -1 -4 |-23
??????????????????????????????????

Click here to see answer by stanbon(75887)

Question 73182: Please help.
solve
{ax + by = b - a
{bx - ay = b - a
Click here to see answer by pradhyumna.kumar@gmail.com(62)

Question 73203: What is the product of this matrix equation using inverse matrices?
[3 -4 x [a = [6
2 1] x b] = 7]
(That is supposed to be a 2x2, a 1x1, and another 1x1. I put the equal and multiplication signs on both top and bottom to make the matrices look a little more aligned.)
Thank you!

Click here to see answer by stanbon(75887)

Question 73815: x-2y+3z=6
2x-y-z=-3
x+y+z=6
Click here to see answer by tazoftroy(22)

Question 73960: Solve for x: [2x 5]=[x 0 1]
[1 3]=[2 -2 4]
=[5 3 1] theres only two matrices. 1 on each side of the equal side

Click here to see answer by Edwin McCravy(20054)

Question 74871: This is actually a total value problem using a graph. How many lbs. of whole milk and cream should be mixed to form 200lbs for cream cheese. whole milk= 4% milk fat, milk for cream cheese = 8 % milk fat and cream =30% milk fat.
Click here to see answer by stanbon(75887)

Question 76542: I need help I don't know how to set it up. Don't know what to do. This problem is from texbook.
Fill 10 gallons of premium gas and a small gas can with 2 gallons of regular gas. You pay $13.56. The price of premium gas is 12 cents more per gallon than theprice per gallon for regular gas.
regular
2 gal. can
premium
10 gal. for car
= $13.56
Click here to see answer by checkley75(3666)

Question 78315: solve each system:
2x- y+3z=-14
3x-2y+4z=11
5x+ y-6z=-32

i am very confused on how to solve this...please help!
Click here to see answer by renevencer22(21)

Question 79410: solve using cramers rule:
2x-3y-3z=25
3x+1y-1z=-5
5x-2y-4z=32

I am very confused with this problem...please help!
Click here to see answer by Edwin McCravy(20054)

Question 79477: Please someone help me! I have to put this in rref and I can't seem to figure out how! I just keep going around in circles!

x-y+z=-3
x+y+z=-9
x+y-z=1
Click here to see answer by chitra(359)

Question 80198: 2X-3Y-2Z=12
X+4Y+Z=-9
4X+2Y-3Z=6
Question: Solve using linear combination and by matrices. Write the matrices you typed into calculator and the operations it took to solve the system

Click here to see answer by stanbon(75887)

Question 80447: You have to solve the equations using matrices. I can get part of the answer correct but not the whole answer. I can solve for y, but what I come up with for x is not correct according to the book. The two equations are:
12x + 2y = 2 and 6x - 3y = -11
I can come up with 3 for y but I end up with -11/6 for x and the book says it should be -1/3. I can't figure out how to get the -1/3.
Click here to see answer by Edwin McCravy(20054)

Question 80576: Find the value for the following determinate.
5 9
2 -3
Click here to see answer by stanbon(75887)

Question 80919: If p, q, and r are positive integeres and the following is true p + 1/(q + 1/r) = 25/19, then find q.

Click here to see answer by ankor@dixie-net.com(22740)

Question 81905: Solve the system using an augmented matrix. Show you work
5x + 4y - z = 1
2x - 2y + z = 1
-x - y + z = 2
Click here to see answer by Edwin McCravy(20054)

Question 82428: Solve each matrix equation for X
1 0 0
0 1 0
0 0 1 X
= 4
-5
3
Click here to see answer by jim_thompson5910(35256)

Question 82431: 0 0 2
0 0 1 X
1 1 1
=
3
4
3
Click here to see answer by stanbon(75887)

Question 82427: 1 1
1 -1 X
= 3
-1
Click here to see answer by stanbon(75887)

Question 82426: Solve each matrix for equation for X
1 2
1 -2 X =
2
-2
Click here to see answer by stanbon(75887)

Question 82714: Use Cramer's rule to solve. If inconsistent or dependent, so state.
11x + 3y = 1
5x + 2y = 4
Click here to see answer by stanbon(75887)

Question 82718: Evaluate the determinant
6 5 6
1 1 3
2 5 1
Click here to see answer by stanbon(75887)

Question 83015: Please help. I have been working this problem for three days and keep getting different answers. My downfall is the signs, I think.
Use Cramer's Rule to solve the linear system
4x + 3y - z = 12
x - 3y + 3z = 14
3x + y + z = 18
I know that D = 4 3 -1
1 -3 3
3 1 1
Dx= 12 3 -1
14 -3 3
18 1 1
Dy= 4 12 -1
1 14 3
3 18 1
I understand how to proceed but the signs are giving me a headache. I am at the point that I just want to view the right answer in its entirity to see where I am going wrong. Thanks in advance.
Click here to see answer by scott8148(6628)

Question 83031: EVALUATE THE DETERMINANT OF THE MATRIX
(6 2) THE ANSWER I GOT WAS -18+-2=-20
(-1 -3) But the answer the teacher gave me was 18+2=-16
and I was wondering how is that not negative and could you please explain to me what exactly is a determinant.
Click here to see answer by bucky(2189)

Question 83333: I have been working on this for days. If anyone can help, I would appreciate it. I have to show all of my work.
Solve using addition, Cramers Rule or matrix.
2x + y - 3z + 4s + t = -2
3x + 2 y - 2z - s + 2t = 7
x - y + z - 2s - 2t = 0
-x - 2y - z + 2s + t = 5
2x + 2y - 2z +s + 2t = 3

Click here to see answer by jim_thompson5910(35256)

Question 83370: WHAT IS THE DEFINITION OF MATHEMATICAL COMPUTATION?
Click here to see answer by mathman409(67)

Question 83881: Hi, Please help me with this one:
If , which of the following must be true? The exponent is actually 1/2 (not .5), I just didn't know how to input it using the plot formula. The answer is but I don't know why. Thanks!
Click here to see answer by stanbon(75887)

Older solutions: 1..45, 46..90, 91..135, 136..180, 181..225, 226..270, 271..315, 316..360, 361..405, 406..450, 451..495, 496..540, 541..585, 586..630, 631..675, 676..720, 721..765, 766..810, 811..855, 856..900, 901..945, 946..990, 991..1035, 1036..1080, 1081..1125, 1126..1170, 1171..1215, 1216..1260, 1261..1305, 1306..1350, 1351..1395, 1396..1440, 1441..1485, 1486..1530, 1531..1575, 1576..1620, 1621..1665, 1666..1710, 1711..1755, 1756..1800, 1801..1845, 1846..1890, 1891..1935, 1936..1980, 1981..2025, 2026..2070, 2071..2115, 2116..2160, 2161..2205, 2206..2250, 2251..2295, 2296..2340, 2341..2385, 2386..2430, 2431..2475, 2476..2520, 2521..2565, 2566..2610, 2611..2655, 2656..2700, 2701..2745, 2746..2790, 2791..2835, 2836..2880, 2881..2925, 2926..2970, 2971..3015, 3016..3060, 3061..3105, 3106..3150, 3151..3195, 3196..3240, 3241..3285, 3286..3330, 3331..3375, 3376..3420, 3421..3465, 3466..3510, 3511..3555, 3556..3600, 3601..3645