Questions on Algebra: Expressions involving variables, substitution answered by real tutors!

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Question 71164: Cell phone plan.
It costs $30.00 per month plus $0.30 per each additional minute over 200 minutes.
Write an expression for the monthly cost of n additional minutes.
Use the expression to find the total monthly cost for 85 additional minutes.
How do I write the expression? Please help!

Click here to see answer by ankor@dixie-net.com(15660)

Question 71187: The product of two consecutive positive even integers is 360. Find the integers.
Let the x=first even integer. Then x+2 is the next even integer.
Their product is 360: x(x+2)=360.
You have a quadratic: x^2+2x-360=0
Factor: (x-18)(x+20)=0
x=18, x+2=20
18*20=360
The integers are 18 and 20.

Click here to see answer by elima(1433)

Question 71191: An employee who produces x units per hour earns an hourly wage of y = 0.55x + 8 (in dollars). Find the hourly wage for an employee who produces 9 units per hour.
Click here to see answer by checkley75(3666)

Question 71189: Carla invested $28,000, part at 14% and part at 9%. If the total interest at the end of the year is $3,370, how much did she invest at 14%?

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Question 71190: The length of a rectangle is 8 in. more than twice its width. If the perimeter of the rectangle is 64 in., find the width of the rectangle.
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Question 71186: Enrique puts 12% of his monthly paycheck in an IRA. If he invests $72 in his IRA, how much was his paycheck?
Click here to see answer by checkley75(3666)

Question 60936: I don't understand on how to solve complex fractions with unlike denominators.
Please help.
4/3xyz^2+2/xyz-2/3z^2
Thank-YOu
Click here to see answer by hailu(13)

Question 71184: Divide. -5/0
Click here to see answer by bucky(2189)

Question 71201: How do I solve the following equation for "f"?
a=(2pirf)^2/r
This is how far I got:
a=4pi^2r^2f^2/r
a=4pi^2rf^2
a/4pi^2r=f^2
If this is correct so far, where do I go from here?
Click here to see answer by ankor@dixie-net.com(15660)

Question 71237: Hi, thank you for taking your time to help me. There is problem #17. In Lewis Carroll's Through the Looking Glass, Tweedledum says to Tweedledee, "The sum of your weight and twice mine is 361 pounds. Then Tweedledee says to Tweedledum, "Contrariwise, the sum of your weight and twice mine is 362 pounds.Find the weight of Tweedledum and Tweedledee
#18. During a publicity campaign, a cycle shop gave away 5000 miniature cycles and bumper stickers. The cycles cost .63 each and the bumper stickers cost .52 each. The cycle shop spent $2798 on the gifts. How many of each gift did he buy?

#20.Solve the problem below. Then write an argument that would convince a classmate that your solution is correct.
Several ancient Chinese books include problems that can be solved by translating to systems of equations. Arithmetical Rules in Nine Sections was compiled by Chang Tsang, a Chinese matematician who died in 152 B.C. One of the problems is:Suppose there are a number of rabbits and pheasanta confined in a cage. In all, there are 35 heads and 94 feet. How many rabbits and how many pheasants are there?
I tried to guess and check for this one..but I couldn't figure anything out & my teacher wanted us to try and write equations for the problems..but I can't find no other way then guess and check. Thanks again for your help!
Click here to see answer by Earlsdon(6287)

Question 71059: Solve for x: a/(x-3a)=b/(x+3b)
Click here to see answer by ankor@dixie-net.com(15660)

Question 71183: One day, the temperature at 2:00 A.M. was 43°F, and by 3:00 P.M. the temperature was 56°F. What was the hourly rate of temperature change?
thanks
Click here to see answer by checkley75(3666)

Question 71334: martin and anna buy books at a sale. martin buys 3 hardcover books and 4 paperback books for $6.50. Anna buys 2 hardcover books and 6 paperback books for $6.00. What is the cost, in dollars, of each hardcover book?
Click here to see answer by checkley75(3666)

Question 71460: Martina leaves home at 9 a.m., bicycling at a rate of 24 mi/h. Two hours later, John leaves, driving at the rate of 48 mi/h. At what time will John catch up with Martina?
Click here to see answer by checkley75(3666)

Question 71459: A bus leaves a station at 1P.M. traveling west at an average rate of 44 mi/h. One hour later a second bus leaves the same station, traveling east at a rate of 48 mi/h. At what time will the two buses be 274 miles apart?
Click here to see answer by checkley75(3666)

Question 71457: A bicyclist rode into the country for 5hours. In returning, her speed was 5mi/h faster and the trip took 4 hours. What was her speed each way?
Click here to see answer by checkley75(3666)

Question 71531: A cell phone company charges $27.95 per month and 12 cents a min for local calls. Another cell phone company charges $12.95 a month and 32 cents a min for local calls. For what number of minutes of local calls is the cost of the plans same?
Click here to see answer by ptaylor(2048)

Question 71610: abs value of 2y+7 = 9
Click here to see answer by checkley75(3666)

Question 71606: " A full bucket of water weighs 8 kilograms. If the water weighs 5 times as much as the bucket empty, how much does the water weigh?"
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Question 71609: absolute value of x-4 = 3
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Question 71737: x+ 3y=16
2x-y=4
How do I rearrange these equasions to find x and y?
Click here to see answer by stanbon(57384)

Question 71735: 8x-5y=-9,3x+5y=-2
Click here to see answer by checkley75(3666)

Question 71702: Solve by substitution
2y=x+6
-3x+2y=-2
Thank you for your help with this.
Click here to see answer by checkley75(3666)

Question 71801: x+y = 250
5x+10y = 21.25
Can you help me solve this equation. In my problem x= nickles and y=dimes, how many dimes and how many nickles do I have?
Thanks for your help, could you please show me the work. I am trying to help my son, he is in 9th grade Algebra I. This question is not from his text book, just a handout from his teacher.
Nancy
Click here to see answer by ankor@dixie-net.com(15660)

Question 71922: at the highschool band's annual spaghetti dinner, the members served 210 dinners and collected $935. the band leader did not designate which ticket was an adult or child dinner. you need to know that to prepare the correct amount of food and for future planning. each adult dinner costs $6 and each child's dinner cost $3.50.
let a = number of adult dinners and c = number of child dinners
a. write two equations to represent the total amountraised from the dinner and the total number of adult and children's dinners sold.
b. how many adult dinners were sold and how many child dinners were sold?
Click here to see answer by stanbon(57384)

Question 71968: Bob invested $19,000, part at 14% and part at 1%. If the total interest at the end of the year is $840, how much did he invest at 14%?
Click here to see answer by stanbon(57384)

Question 71972: A consultant traveled 4 hours to attend a meeting. The return trip took only 3 hours because the speed was 7 miles per hour faster. What was the consultant's speed each way?
Click here to see answer by Earlsdon(6287)

Question 71942: simplify: 1 over a + 2 over 3b divided by 1 over 2b - 3 over a.
this is a different question:
what number can not be used to replace the variable in
3 over x+1 and x-2 over 4

Click here to see answer by stanbon(57384)

Question 72019: A long-distance phone call costs $1.28 for the first minute and $0.78 for each additional minute or portion thereof. Write an inequality representing the number of minutes a person could talk without exceeding $8.
Click here to see answer by checkley75(3666)

Question 72525: (n+1/3)+(n+2/4)=1
Click here to see answer by jim_thompson5910(28598)

Question 72660: The algebra problems I'am submitting are the ones I'am having a problem with, thanks for the help.
5x - 2y = -5
y - 5x = 3
Click here to see answer by stanbon(57384)

Question 72669: I have tried this several different ways. I don't know how to do it. Please help.
Solve for x,y,z
3x+2y-4z=-100
4x-3y+2z=80
5x-4y-z=-120
Click here to see answer by ankor@dixie-net.com(15660)

Question 72736: what is f(2a)=3x+5
Click here to see answer by stanbon(57384)

Question 72802: I am having trouble with the rules for postive and negative numbers. when adding,subtract multiply and divide please help thanks
Click here to see answer by checkley75(3666)

Question 72816:
Click here to see answer by rahman(247)

Question 72954: Find the exact solution to the equation 3^x+5 = 9^x.
I submitted this once but I think I forgot to complete my email address
Click here to see answer by stanbon(57384)

Question 72972: I really don't understand any of this substitution stuff so i was wondering if you could help me understand
Click here to see answer by jim_thompson5910(28598)

Question 72790: Which label describes the following?
3x + 6 = 10
A.Expression
B.Linear equation
C.Equation which is not linear
Click here to see answer by elima(1433)

Question 73094: Please help i so do not understand this.
Find the constant of variation k.
m varies directly with n; m = 144 when n = 8.

Click here to see answer by rmromero(383)

Question 73091: Solveand show work. x/6 + 1 = 3

Click here to see answer by rmromero(383)

Question 73126: can i have help solving this system using the elimination method and separately help solving it using Cramer's rule?...
s + p + c = 40
c = 4p
s = p - 2
Click here to see answer by bucky(2189)

Question 73133: can you help me solve this system using the elimination method?
s + p + c = 40
c = 4p
s = p - 2
Click here to see answer by bucky(2189)

Question 73145: Can you help me solve this equation for s?.... s = p - 2 = 7 - 2 = 5

and help solve this one for c?.... c = 4 * p = 4 * 7 = 28

please and thank you!!
Click here to see answer by jim_thompson5910(28598)

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