Questions on Algebra: Systems of Linear Equations answered by real tutors!

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Question 100795: Solve by substitution.
-4x+y= -11
2x-3y= 5
I started by isolating "x" in 2nd equation: 2x = 3y+5. I substituted the "x" in the 1st equation: -4(3y+5)+y+ -11 to get: -12y-20+y= -11.
I combined like terms to get: -11y = 9 , to get the solution for "y" - 9/11. Is this correct? If so, how do I get "x" solution?
Click here to see answer by jim_thompson5910(28598)

Question 101019: Biotech Company is selling their product in single units for $4.17 each and in bulk bundles of 10 which cost $25.85 per bundle.
They sell 829 units of their product in one day which gives them a gross revenue of $2,426.68.
How many single units and how many bundles did they sell that day?
here is what i have so far:
4.17x + 25.85y = 2426.68
x + y = 829
for some reason i can't get the answer to work out.
Click here to see answer by doukungfoo(195)

Question 101028: Could someone please help me solve this question: Solve the following system of two linear equations by substitution: x + 2 y – 8 =0 & 2 x + 4 y + 4 =0.
Noting each equation represents a line, draw both lines and interpret the results.
Thank you, for taking the time to help me.
Click here to see answer by stanbon(57377)

Question 101077: y-2x=0
Click here to see answer by tutorcecilia(2152)

Question 101073: How do I do this?
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?

Let a = the number of adult tickets purchased.
Let s = the number of student tickets purchased.
a. Write a system of equations that can be used to determine the number of adult and student tickets purchased.
b. Determine the number of adults tickets sold and the number of student tickets sold. Use mathematics to explain how you determined your answer.

Click here to see answer by checkley71(8403)

Question 101076: How do I work this problem?
Suppose you just have just enough dimes and quarters to pay for a loaf of bread and quart of milk, which cost $3.45. You have a total of 15 dimes and quarters.
Let d = the number of dimes you have.
Let q = the number of quarters you have.
a. Write a system of equations that models the information given above.
b. Solve the system for the number of dimes and quarters you have. You may want to solve this by graphing.

Click here to see answer by edjones(7569)

Question 101075: Your family likes to go to baseball games. At one game your family bought 5 soft drinks and 5 hot dogs for $22.25. At the next game your family attended they bought 4 soft drinks and 3 hot dogs for $14.50. What is the cost of one soft drink and one hot dog?
Let s = the cost of one soft drink
Let h = the cost of one hot dog
a. Write a system of equations modeling the situation described above.
b. Solve the system for the cost of one soft drink + one hot dog. (You will have to add your solutions together for this one.)

Click here to see answer by stanbon(57377)

Question 101122: sum of the digits of a two no. is 9 the no. obtained by interchanging the digits exceed the given no. by 27 find the given no.
Click here to see answer by checkley71(8403)

Question 101103: Solve the system;
3x+4y=23
2x-5y=-23
Click here to see answer by jim_thompson5910(28598)

Question 101192: 4x^2+2x-3=0. Solve by completing the square. (4x^2 is 4x squared)
Click here to see answer by jim_thompson5910(28598)

Question 101202: I'm having trouble trying to figure out this problem, please help.
2/3(p+3) > 5/6(p-4)
Click here to see answer by MathLover1(6634)

Question 101072: Can someone help me with this?
Six pears and three apples cost $3.90. Two pears and five apples cost $3.30. How much does one pear cost? Hint: You have two unknowns (variables), so you need two equations. Write one equation for each situation and solve the system of equations.
Let p = the cost of one pear
Let a = the cost of one apple
a. Write a system of equations that can be used to determine the cost of pears and apples.
b. Determine the cost of one pear and one apple. Use mathematics to explain how you determined your answer

Click here to see answer by stanbon(57377)

Question 101074: help!!
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. This similar to the current problem as you have to consider the 25 mph tailwind and headwind.
Let r = the rate or speed of the airplane in still air.
Let d = the distance
a. Write a system of equations for the airplane. One equation will be for the outbound trip with tailwind of 25 mph. The second equation will be for the return trip with headwind of 25 mph.
b. Solve the system of equations for the speed of the airplane in still air.

Click here to see answer by scott8148(6628)

Question 101067: How do I do this?
At the market you purchase some apples and oranges. There were 12 items purchased. You buy twice as many apples as oranges.
a. Define the variables.
b. Write an algebraic equation using one variable for the above situation.
c. Solve this equation for the number of apples and oranges you purchase
Click here to see answer by scott8148(6628)

Question 101261: a defective briefcase costing rs.800 is being sold at a loss of 8% if the price is further reduced by 5% find its selling price.
Click here to see answer by stanbon(57377)

Question 101260: ravish sold his motor cycle to vineet at a loss of 28% vineet spent rs. 1680/-on its repair and sold the motor cycle to rahul for rs. 35910, thereby making a profit of 12.5% find the cost price of the motor cycle for ravish.
Click here to see answer by stanbon(57377)

Question 101338: Could you please take the time to help me solve this question: Solve the following system of three linear equations: 2x + y + z = 3, -x + 2y + 2z = 1 and x - y - 3z = -6. Noting that each equation represents a plane, interpret your results.
Thank you, very much for taking the time to help me, most appreciated
Click here to see answer by MathLover1(6634)

Question 101121: the perimeter of rectangle 240 cm. its length is decreased by 10% & its breadth increased by 20 we get the same perimeter find the length & breadth of rectangle
Click here to see answer by ankor@dixie-net.com(15659)

Question 101409:
Click here to see answer by MathLover1(6634)

Question 101419: sketch the graph of f(x)=x^2-6x+11
Click here to see answer by stanbon(57377)

Question 101417: find the inverse function for f(x)-5x^2+12.
Click here to see answer by edjones(7569)

Question 101466: If the reciprocal of 4 times a number is subtracted from the reciprocal of that number, the result is 1/12. What is the number?
Click here to see answer by scott8148(6628)

Question 101467: If the reciprocal of 4 times a number is subtracted from the reciprocal of that number, the result is 1/12. What is the number?
Click here to see answer by scott8148(6628)

Question 101468: If the reciprocal of 4 times a number is subtracted from the reciprocal of that number, the result is 1/12. What is the number?
Click here to see answer by scott8148(6628)

Question 101469: If the reciprocal of 4 times a number is subtracted from the reciprocal of that number, the result is 1/12. What is the number?
Click here to see answer by scott8148(6628)

Question 101470: If the reciprocal of 4 times a number is subtracted from the reciprocal of that number, the result is 1/12. What is the number?
Click here to see answer by scott8148(6628)

Question 101473: Evaluate the expressions if x = -2, y = 5, and z = -2: -5(-3y - 2z)
Click here to see answer by praseenakos@yahoo.com(507)

Question 101413: solve 2x^2-3x-14=0
Click here to see answer by oberobic(2304)

Question 101416: find the slope intercept form of a line that passes through A(8,3) and B(-7,-5)
Click here to see answer by edjones(7569)

Question 101612: We're back.
Consecutive Intergers - Write the equation and solve.
The problem: Twice the greater of two consecutive odd integers is 13 less than three times the lesser. What are the integers.
Click here to see answer by scott8148(6628)

Question 101664: Please help with this problem
1/2x - 2 = 1/3(x-2)
Your help will be greatfully appreciated because I'm confused.
Click here to see answer by scott8148(6628)

Question 101854: The sum of three times a number and 7 more than the number is the same as the difference between -11 and twice the number. Find the number.
Click here to see answer by stanbon(57377)

Question 101667: Please help with this problem
1/2x - 2 = 1/3(x-2)
Your help will be greatfully appreciated because I'm confused.
Click here to see answer by ankor@dixie-net.com(15659)

Question 101867: Bruce Springsteen and the E Street Band generated top revenue on the concert circuit in 2003. Springsteen and second-place Celine Dion together took in $196.4 million from ticket sales. If Celine Dion took $35.4 million less than Bruce Springsteen and the E Street Band, how much revenue did each generate?
Click here to see answer by doukungfoo(195)

Question 101979: The x represents an integer, how can you express the next smaller consecutive integer in terms of x?
Click here to see answer by stanbon(57377)

Question 101999: If the sum of three consecutive even integers is 60, what is the first of the three even integers?
Click here to see answer by bucky(2189)

Question 101996: Find two consecutive even integers such that the lesser added to three times the greater gives a sum of 46.
Click here to see answer by mathemanic(13)

Question 101972: The sum of the measures of the angles of any triangle is 180 degrees. In triangle ABC, angles A and B have the same measure, while the measure of angle C is 60 degrees greater than each of A and B. What are the measures of the three angles?
Click here to see answer by MathLover1(6634)

Question 102155: Hi, Can you please help with this equation? I have a test first thing tomorrow morning and I am very stuck. I know what the answers should be, (x=1.5 and y=-0.8) but and having trouble getting there.
The equation is as follows:
1.2(x+4)-2.5(3y-2) = 2
4/5(3x-5)+ 3/2(3y-4) = -10
This is what I've got so far:
1.2(x+4)-2.5(3y-2) = 2
.08(3x-5)+1.5(3y-4) = -10
1.2x + 4.8 -7.5y+5 = 2
2.4x-4 + 4.5y-6 = -10
1.2x + 9.8 -7.5y = 2
2.4x -10 + 4.5y = -10
2.4x x -7.5 -10x-7.5 +4.5y-7.5 = 10x-7.5
-18x +75 -33.75y = -75
1.2x-18x +9.8+75 - 7.5y-33.75y = -75+2
16.8x + 84.8 - 41.25y = 77

Click here to see answer by stanbon(57377)

Question 102166: Solve the system of equation
5x+y=12
2x=3y-19
Click here to see answer by checkley75(3666)

Question 102115: Mr. Calvillo wants to enclose a rectangular area for a garden space of a given square footage. The length of the plot will vary inversely as the width. If her decides on a width of 18 feet, the garden will be 30 feet long. How long will a 45-foot wide garden be?
Click here to see answer by elima(1433)

Question 102274: Solve the system by the addition method:
Eq 1 states: 3x = 3 + 2y
Eq 2 states: -4/3x + y = 1/3
Click here to see answer by stanbon(57377)

Question 102280: trying to help my son...everyone in the house has worked and we get different answers. Please help us to understand! Gets confusing w/all the fractions...
c/2 - d/5 = -4;2c/3 -3d/5 = -7
thank you!
Click here to see answer by Fombitz(13828)

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