# Questions on Algebra: Linear Algebra (NOT Linear Equations) answered by real tutors!

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 Algebra: Linear Algebra (NOT Linear Equations) Solvers Lessons Answers archive Quiz In Depth

 Question 103908: I need to factor this problem. 8x^3y^2 - 18xy^4 Click here to see answer by jim_thompson5910(29613)
 Question 103908: I need to factor this problem. 8x^3y^2 - 18xy^4 Click here to see answer by stanbon(60771)

 Question 103860: if f(x)=2x*2-3x+4, find 1-f(0) 2-f(1) 3-f(2) 4-f(-2) 5-f(1/2) Click here to see answer by checkley75(3666)

 Question 105005: Solve the system using any algebraic method: 7x+5y=-12 3x-4y=1 Click here to see answer by elima(1433)

 Question 105059: A change machine contains nickels, dimes, and quarters. There are 75 coins in the machine, and the value of the coins is \$7.25. There are 5 times as many nickels as dimes. Find the number of coins of each type in the machine. Click here to see answer by ankor@dixie-net.com(16523)

 Question 105057: 45,500A company placed \$1,000,000 in three different accounts. It placed part in short-term notes paying 4.5% per year, twice as much in government bonds paying 5%, and the rest in utility bonds paying 4%. The income after one year was \$45,500. How much did the company place in each account? Click here to see answer by checkley75(3666)

 Question 105860: ok so this is my equation. and i get it and all its just i cant get it to work but the teacher told us that i had to be in whole answers -2x+y+z=-2 5x+3y+3z=71 4x-2y-3z=1 this is what i have tried so far.. 5x+3y+3z=71 4x-2y-3z=1 ----------- 9x+y=72 and then from there i have tried them all, and it just wont come out.! please help me.! Click here to see answer by scott8148(6628)

 Question 106052: Write the equation of the line passing through each of the given pairs of points. Write your result in slope-intercept form, where possible. Points: (2,-3) and (2,4) Thanks....again! Click here to see answer by MathLover1(7480)

 Question 106047: Find the slope of any line perpendicular to the line though points (0,5) and (-3,-4) Thank you Click here to see answer by Fombitz(13828)

 Question 106210: You worked 14 hours last week and earned a total of \$96.00 before taxes. Your job as a lifeguard pays \$8.00 per hour, and your job as a cashier pays \$6.00 per hour. How many hours did you work at each job? I have a problem similar to the above. But can't remember how to set up the solution. My guess is 8x + 6y = 96 Click here to see answer by bucky(2189)
 Question 106210: You worked 14 hours last week and earned a total of \$96.00 before taxes. Your job as a lifeguard pays \$8.00 per hour, and your job as a cashier pays \$6.00 per hour. How many hours did you work at each job? I have a problem similar to the above. But can't remember how to set up the solution. My guess is 8x + 6y = 96 Click here to see answer by jamaicanboy(1)

 Question 106606: Here is one of the hardest problems I have even seen! Can you please see if you can help with this one? I feel like I can write some functions, but I am really confused. Product x: Each item sold produces \$100 profit Labor cost: is 3 hours for assembly, 1 hour in detail work, and 2 hours for QA & packing product. Product y: Each item sold produces \$150 profit Labor cost: is 5 hours for assembly, 3 hour in detail work, and 2 hours for QA & packing product. Company has these hours available for production for each accounting period: 3900 hours for assembly, 2100 hours for detail work, & 2200 hours for QA & packing. Questions are: 1) How many products of both x & y should be produced to make a max & min profit? 2) Now what if product y profit goes up to \$170 each. How many products are needed to make a max & min profit? I know this is not an easy question, but do you think you could help with this question please? Thank you kindly. Click here to see answer by stanbon(60771)

 Question 106669: 6x + 4(3x – 2) = 6x + 2 I am getting x=10 but I was not sure if I did it right. Click here to see answer by rcmcc(152)
 Question 106669: 6x + 4(3x – 2) = 6x + 2 I am getting x=10 but I was not sure if I did it right. Click here to see answer by Earlsdon(6294)

 Question 107040: i need help solving these quadratic equations using the quadratic formula. 2x^2 - 5x = 3 3x^2 - 2x + 1 = 0 Click here to see answer by bucky(2189)

 Question 107041: i need help solving these quadratic equations using the quadratic formula. 2x^2 - 5x = 3 3x^2 - 2x + 1 = 0 Click here to see answer by HyperBrain(694)

 Question 107039: i need help solving these quadratic equations using the quadratic formula. 2x^2 - 5x = 3 3x^2 - 2x + 1 = 0 Click here to see answer by josmiceli(10616)

 Question 107135: Reaction time problem: When you are pricked with a pin, there is a short time delay before you say "ouch!" This reaction time varies linearly with the distance between your brain and the place you are pricked. Dr. Hollers pricks Leslie Morley's finger and toe, and measures reaction times of 15.2 and 22.9 milliseconds, respectively. (A millisecond is 1/1000 of a second.) Leslie's finger is 100 cm from the brain, and her toe is 170 cm from the brain. a) Write the particular equation expressing time delay in terms of distance. b) How long would it take Leslie to say "ouch" if pricked in the neck, 10 cm from the brain? c) What does the time-intercept equal, and what does it represent in the real world? d) Since the slope is in millisecons per centimeter, its reiprocal is the speed whick nerve impulses travel in centimetes per millisecond. How fast do the impulses travel in cm/sec? e) Sketch and label the gragh. Click here to see answer by Fombitz(13828)

 Question 107124: Let {a1,...,ap} be a set of vectors from R^n. If a1=x2a2+...+xpap where x2...xp are scalars, then span(a1...ap) = span(a2...ap). I need assistance showing that this statement is true. Click here to see answer by jim_thompson5910(29613)

 Question 105380: Solve the system by addition x + y = 6 x – y = 4 Click here to see answer by Joeshie(9)

 Question 107134: Milk Problem: Handy Andy sells one-gallon cartons of milk (4 quarts) for \$3.09 each and half-gallon cartons for \$1.65 each. Assume that the number of cents you pay for a carton of milk varies linearly with the number of quarts the carton holds. a) Write the particular equation expressing price in terms of quarts. b) If Handy Andy sold 3-gallon cartons, what would your equation predict the price to be? c) The actual prices for pint cartons (1/2 quart) and one-quart cartons are \$.57 and \$.99, respectively. Do these prices fit your mathematical model? If not, are they higher than predicted or lower? d) Suppose that you found cartons of milk marked at \$3.45, but that there was nothing on the carton to tell what size it is. According to your model, how much would such a carton hold? e) What doe the price-intercept represent in the real world? f) What are the units of the slope? What real-world quantity does this number reprsent? g) Sketch and label the graph. Click here to see answer by Joeshie(9)

 Question 107324: solve the following sytems of equations 1. 2. 3. y=7x-8 6x+7y=19 3x-2y=4 y=3x-12 x+y=5 2x+y=12 Click here to see answer by elima(1433)

 Question 107512: I am trying to help my daughter with her homework, but since I have no idea what I am doing I hope that having the answer will help me out: Cricket Problem: Based on information in Deep River Jim's Wilderness Trailbook, the rate at which crickets chirp is a lenear function of temperature. At 55 degrees F they make 70 chirps per minute and at 69 degrees F they make 126 chirps per minute. a) Write the equation expressing chirping rate as a function of temperature. b) Predict the chirping rate at 90 degrees F. c) How warm is it if they are chirping 120 chirps per minute? d) Calculate the temperature-intercept. What does this tell you about this numbeer in the real-world? e) Calculate the chirping-intercept. What does the chirping-intercept tell you about the real-worl? f) Shetch and label the graph. Thank you for any help. Brian Click here to see answer by stanbon(60771)
 Question 107512: I am trying to help my daughter with her homework, but since I have no idea what I am doing I hope that having the answer will help me out: Cricket Problem: Based on information in Deep River Jim's Wilderness Trailbook, the rate at which crickets chirp is a lenear function of temperature. At 55 degrees F they make 70 chirps per minute and at 69 degrees F they make 126 chirps per minute. a) Write the equation expressing chirping rate as a function of temperature. b) Predict the chirping rate at 90 degrees F. c) How warm is it if they are chirping 120 chirps per minute? d) Calculate the temperature-intercept. What does this tell you about this numbeer in the real-world? e) Calculate the chirping-intercept. What does the chirping-intercept tell you about the real-worl? f) Shetch and label the graph. Thank you for any help. Brian Click here to see answer by Fombitz(13828)
 Question 107512: I am trying to help my daughter with her homework, but since I have no idea what I am doing I hope that having the answer will help me out: Cricket Problem: Based on information in Deep River Jim's Wilderness Trailbook, the rate at which crickets chirp is a lenear function of temperature. At 55 degrees F they make 70 chirps per minute and at 69 degrees F they make 126 chirps per minute. a) Write the equation expressing chirping rate as a function of temperature. b) Predict the chirping rate at 90 degrees F. c) How warm is it if they are chirping 120 chirps per minute? d) Calculate the temperature-intercept. What does this tell you about this numbeer in the real-world? e) Calculate the chirping-intercept. What does the chirping-intercept tell you about the real-worl? f) Shetch and label the graph. Thank you for any help. Brian Click here to see answer by solver91311(18785)

 Question 107513: I am trying to help my daughter with her homework, but since I have no idea what I am doing I hope that having the answer will help me out: Cost of owning a car problem: The number of dollars per month it costs you to own a car is a function of the number of miles per month you drive it. Based on information in an issue of Time magazine, the cost varies linearly with the distance and is \$376 per month for 400 miles per month and \$572 per month for 1800 miles per month. a) Write the particular equation expressing cost in terms of distance. b) Predict the monthly cost if you drive 500, 1000, 2000 miles per month. c) About how far could you drive in a month without exceeding a monthly cost of \$600? d) What does the slope reprsent? e) List all the resons you can think of to explain why the dollars per month intercept is grater than zero. f) Sketch and label the graph. Thank you in advance for any help you can give me. Brian Click here to see answer by scott8148(6628)

 Question 108375: The problem is a word problem that reads as follows: Moira has \$2.95 half dollars, dimes, and nickels. The number of half-dollars is 1 less than twice the number of dimes. The sum of the number of half-dollars and the number of nickels is 8. Find the number of coins of each type. Please help me. I made three equations, and tried to solve the system but could not get the answer. It would be a big help. Thank you! Click here to see answer by ankor@dixie-net.com(16523)

 Question 108241: how do solve for the linear combination method Click here to see answer by elima(1433)

 Question 108525: How do you graph an absolute value equation accurately? On the other hand, how do different types of equations transform y=/x/? Click here to see answer by Fombitz(13828)

 Question 105470: Let p0 = (x0,y0,z0)and p = (x,y,z). Describe the set of all points (x,y,z) for which ||p-p0|| = 1. Click here to see answer by wgunther(43)

 Question 109096: I am helping my daughter with her homework and have no idea what I am doing, hope you can help. Gas tank problem. Suppose that you get your car's gas tank filled up, then drive off down the highway. As you drive, the number of minutes, t, since you had the tank filled and the number of liters, g, remaining in the tank are related by a linear function. After 30 minutes you have 59 liters left. An hour after the fill-up you have 38 liters left. a) Which variable should be independent and which should be dependent? b) Write the particular equation for this function. c) Use the equation to predicit the time when you will run out of gas d) Find the g-intercept and tell what it represents in the real world. e) Tell what the slope represents in the real world, and tell the significance of the fact that the slope is negative. f) sketch the graph. Thank you I hope you can help me, Brian Click here to see answer by scott8148(6628)
 Question 109096: I am helping my daughter with her homework and have no idea what I am doing, hope you can help. Gas tank problem. Suppose that you get your car's gas tank filled up, then drive off down the highway. As you drive, the number of minutes, t, since you had the tank filled and the number of liters, g, remaining in the tank are related by a linear function. After 30 minutes you have 59 liters left. An hour after the fill-up you have 38 liters left. a) Which variable should be independent and which should be dependent? b) Write the particular equation for this function. c) Use the equation to predicit the time when you will run out of gas d) Find the g-intercept and tell what it represents in the real world. e) Tell what the slope represents in the real world, and tell the significance of the fact that the slope is negative. f) sketch the graph. Thank you I hope you can help me, Brian Click here to see answer by edjones(7794)

 Question 109176: Hi! I have a question about solving systems using inverse matrix. (x) (-2 1) (8) (-10) (y) STEP1 = (3/2 -1/2) (6) STEP2 = ( 9) STEP3 How to get from step 2 to step 3? Thanks! Anna Click here to see answer by jim_thompson5910(29613)

 Question 109178: I am helping my daughter with her homework and have no idea what I am doing. Computer diskette problem: A computer store sells 10 floppy diskettes for \$15, and 30 for \$40. Assume that the number of dollars varies linearly with the number of diskettes. a) Write the particular equation expressing dollars in terms of diskettes. b) Predicit the price for a box of 100. c) State the domain for your variable. d) Sketch and label the graph. Click here to see answer by edjones(7794)
 Question 109178: I am helping my daughter with her homework and have no idea what I am doing. Computer diskette problem: A computer store sells 10 floppy diskettes for \$15, and 30 for \$40. Assume that the number of dollars varies linearly with the number of diskettes. a) Write the particular equation expressing dollars in terms of diskettes. b) Predicit the price for a box of 100. c) State the domain for your variable. d) Sketch and label the graph. Click here to see answer by ankor@dixie-net.com(16523)

 Question 109214: 3x-2y+z=2 -x+y=3 -2y+6z=-1 a. provide a coeffient matrix corresponding tp the system of linear equations. B. the transpose is ? is it the switching of rows? c.The determinant? is it the part of a matrix A, det |A| or , is a real number associated with every square matrix. Click here to see answer by jim_thompson5910(29613)

 Question 109179: I need help with my daughters homework!! Reading problem: Phoebe Small still has 35 pages of history to be read after she has been reading for 10 minutes, and 5 pages left after she has been reading for 50 minutes. Assume that the number of pages she has left to read varies linearly with the number of minutes she has been reading. a) Write the particular equation expressing pages in terms of minutes. b) Predict the time when she has finished reading. c) State the domain for the variable. d) Sketch and labe the graph. Click here to see answer by anne(47)