Tutors Answer Your Questions about Linear-systems (FREE)
Question 167863: The problem is dealing with systems of linear equations in more than two variables. I have to solve each system of equations. I have tried but can't seem to get the answer using the substitution or elimination method.
3x + 4y - z = -7
x - 5y + 2z = 19
5x + y - 2z = 5
Click here to see answer by ankor@dixie-net.com(22740)   |
Question 168319: The area of a kite varies jointly with the lengths of its two diagonals. If a kite with the area 30 inches squared has one diagonal of length 10 inches and the other diagonal of length 6 inches, what is the area of a kite with diagonals of length 8 inches and 13 inches?
Click here to see answer by Mathtut(3670) |
Question 168297: Elementary and Intermediate Algebra, 3e ISBN: 9780073533490
Page 487 Number 14
For each problem, write a system of equations in two or
three variables. Use the method of your choice to solve each
system.
14. One night the manager of the Sea Breeze Motel rented
5 singles and 12 doubles for a total of $390. The next night
he rented 9 singles and 10 doubles for a total of $412.
What is the rental charge for each type of room?
Click here to see answer by Mathtut(3670) |
Question 168889: Using Substitution
4x + 2y = 1
2x + 3y = .70
Solving for X in the first problem
4x + 2y - 2y = 1 - 2y
4x = 1-2y
4x/4 = (1-2y)/4
x = (1 - 2y)/4
Substitute x into first equation (this is where I get lost)
2(1-2y/4) + 3y = .70
the example on this website says it should be 2(1+2y)/4+3y=.70, but if x = (1-2y)/4, how can you just change it to the 1+2y? Then also how do I solve the problem? If you could give me step by step with explanations so I understand that would be very helpful. This is my calculations:
2-4y/4 + 3y = .70 (multiplied 2 by everything in parentheses)
2-y+3y=.70 (4's cancel eachother out)
2+2y=.70 (3y minus 1y = 2y)
2+2y/2 = .70/2 (divide both sides by 2)
1+y = .35
y = .35 - 1 (subtract 1 from each side)
y = -.65
Click here to see answer by Fombitz(32388)  |
Question 169187: Hello, I just need help with how to solve this equation:
y-1/5x=-2
I know how to solve the problems, but only if there in simplified form already.. You don't have to give me the answer but just tell me how to simplfy it.
Thank you!!
Click here to see answer by Alan3354(69443)  |
Question 169669: I am a math tutor on this site, can someone please help with a method of systems of equations?
I need to know the name of this method of solving
Ex.
.
.
.
First solve for a variable, we will solve for "x" in each equation
.
First equation,
.
, move "4y" to the right side
.
=  =  or 
.
 is our first answer, keeping that answer in mind we solve for "x" in the other equation
.
Second equation,
.
, move (-y) to the right side
.
=  =  or  , now divide each side by "2"
.
=  = 
.
Second answer is  , then I would say, since these two answers equal "x" both answers will equal each other, then I would put them in an equation
.
 , then I would solve for "y"
.
 , then I would show the student the cross multiplication
.
We come up with  , then just solve, in which we would get 
.
Then I would replace "y", and go through the math, and find that 
.
What would you call this method ( when you solve for a variable in both equations, and put your answers together in an equation and solve )
.
Solution set = (20,0)
.
Please don't answer if you don't know the name of this method
.
Thanks ahead of time, Electrified_Levi
Click here to see answer by stanbon(75887) |
Question 169735: Solve this equation: (I am checking my homework to see if i got it right)
4[3-3(x+1)]+1=2(-31-x)2x+31
Here's my work/answer:
12-12x-12+1=-62-2x+2x+31
-12x+1=-50-2x+2x=31
-12x+1=-50-2x+2x+19
-12x=-50-2x+2x+18
-12x=-32
x= 2 2/3
Click here to see answer by Alan3354(69443) |
Question 169770: Problem:
Suppose $8,000 is invested at interest rate k, compounded continuously, and grows to $11,466.64 in 6 years.
a) Find the interest rate
b) Find the exponential growth function
c) Find the balance after 10 years
d) Find the doubling time.
Thank you.
Click here to see answer by Edwin McCravy(20056)  |
Question 169981: Hi, Can you please help?
.
Can you please give me some math problems for my homework?
I need to solve systems of equations
.
Can you please give some systems of equations that I could solve?
.
Keep in mind that I have to solve these equations with both the substitution, and elimination method
.
I would like some easy problems ( with answers with whole numbers, like ( 4,5 ) and ( -1, 8 ) )
.
I would like some medium problems ( with answers with nice fractions such as ( 1/2, - 3/4 ) and ( 2/5, 1/10 )
.
I would like hard problems ( with answers with fractions like ( 43/99, 44/199) and ( - 309/299, 87/77 )
.
I need to at least have 20 - 30 problems. So I need at least 20 people to submit one, or ten submit two, and so forth, ( or if one person could send a lot of them)
.
It doesn't matter if I get 1000(exaggeration) problems, I just need a good number of them.
.
Please send me the answers to my email at Electrified_Levi@yahoo.com
.
Also, if some can give some easy 3 variable equations with whole numbers, or even medium difficulty
.
Thanks
Click here to see answer by jim_thompson5910(35256) |
Question 170032: Hi, Can you please help?
.
When given the system of equations of
.
If you are solving it using elimination
.
This is how I would solve it
.
I would multiply the whole second equation by 
.
 =  = 
.
I would then add this equation with the first equation
.
.
I would then come up with  , then I solve it, and find that "x" = 2, then I would plug in the answer, and find that "y" = (-1)
.
Is this how elimination works?
.
Or do you have to do it this way...
.
.
Multiply the first equation by "7" and the second by "5"
.
I did the math and came up with
.
.
Then add the equations
.
I get  , and then find "x" is "2", and "y" = (-1)
.
I will be doing quizzes soon, and I perfer the first way, but does elimination mean you do it the second way
.
What I am asking is, is it o.k. to do elimination the first way, or is the second way, the right way to do it?
.
Thanks ahead of time, Levi
Click here to see answer by checkley77(12844) |
Question 170179: Solve the system of equations using the substitution method. If the answer is a unique solution,present it as an ordered pair (x,y). If not specify whether the answer is "no solution" or infintely many solutions."
3x+y=7
4x-y=21
Second part of question.
Solve the system of equations using the addition (elimination) method. If the answer is a unique solution, present it as an ordered pair: (x,y). If not specify whether the answer is "no solution" or infintely many solutions.
6x+2y=2
3x+5y=5
Third Part
Solve the system of equations using the addition (elimination) method. If the answer is a unique solution, present it as an ordered pair:(x,y). If not, specify whether the answer is no solution or "infinitely many solutions."
4x-3y=1
-12x+9y=5
Click here to see answer by jim_thompson5910(35256) |
Question 170598: I am so confused by this. My mom tried to help me but she doesn't understand either. There is one of the questions I am supposed to solve. If someone can show me the steps to this one maybe I can figure out the others.
Maria has $7.30 in dimes and quarters. She has 34 coins. How many dimes could she possibly have? Explain your answer. Don't forget to show your work!
(Hint: The problem could be solved using a linear system of equations. Try to set up an equation indicating the number of coins and another equation with their value.)
Click here to see answer by Mathtut(3670) |
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