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

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Question 208955: use the expression r + 0.12m to calculate the cost of renting a car.
The basic rate is r. The number of miles driven is m.
question: The basic rate is $15.95. The car is driven 150 mi.

Click here to see answer by stanbon(57246)

Question 208388: How would I solve the equation listed below using the elimination method? I have tried, but I keep coming up with differnt answers.
x+5y=29
-7x+4y=70
Click here to see answer by jadi929(1)

Question 209131: Im having trouble setting up the equation, please help.
The 2000 U.S. census showed that the population of Alabama was 4,447,000 with 26.0% represented by African-Americans. What is the best estimate of African American population in Alabama.
A.500,000
B.750,000
C.1,100,000
1,500,000
Click here to see answer by rfer(12647)

Question 209289: Factor completely:
x^2 + 12x - 28
Click here to see answer by Earlsdon(6287)

Question 209289: Factor completely:
x^2 + 12x - 28
Click here to see answer by rfer(12647)

Question 209293: There are five people in the room. Each person shakes the hand of every other person exactly once. How many handshakes are exchanged?
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Question 209357: There are 1024 bytes in a kilobyte. write an expression that describes the number of bytes in a computer chip with n kilobytes
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Question 209362: The time required for a race car to complete a 400 mile race is inversely proportional to the average speed that the car maintains. Express the relationship between race time and average speed in two equivalent forms.
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Question 209291: A store recieved 200 containers of juice to be sold by April 1. Each container cost the store $0.75 and sold for $1.25. The store signed a contract with the manufacturer in which the manufacturer agreed to a $.50 refund for every container not sold by April 1. If 150 containers were sold by April 1, how much profit did the store make?
Click here to see answer by rfer(12647)

Question 209339: I need assistance simplifying the following expressions:

---

---
To specify, the last problem's radical has an index of 3, not 3 times the square root of the expression.
Thank you in advance!
Click here to see answer by MathTherapy(1421)

Question 209399: I need help with the following quetion : A firefighter spraying water on a fire stood on the middle of the ladder. When the smoke became less thick the firefighter moved up 4 rungs. However it got too hot, so the firefighter backed down 6 rungs. Later the firefighter went up 7 rungs and stayed until the fire was out. Then the firefighter climbed the remaining 4 rungs and entered the building. How many rungs did the ladder have ?
I did try to work out this problem using a diagram, but im not sure if the answer is right.
Click here to see answer by stanbon(57246)

Question 209628: I am really confused, can you help me?
The function described by H(x) =2.75x +71.48 can be used to predict the height, in centimeters, of a woman whose humerus bone is cm long.
Predict the height of a woman whose humerus is 35 cm long _____cm

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Question 209572: Use substitution to solve
NP+ND=50
NP+10ND=140
Click here to see answer by checkley77(12569)

Question 209712: A goldsmith has two alloys that are different purities of gold. The first is three-fourths pure gold and the second is five-fifths pure gold. How many ounces of each should be melted and mixed in order to obtain a 6-oz mixture that is two-thirds pure gold?
How do I make an equation out of this question?
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Question 209909: seven more than the product of a number and 10
Click here to see answer by Alan3354(30983)

Question 209937: The product of the cube of a number and -6
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Question 210020: can you help me I dont get this if there are 1024 bytes a kilobyte write an expression that describes the number of bytes in a computer chip with n kilobytes
Click here to see answer by stanbon(57246)

Question 210093: -2x-18=6(1-2x)+4x

Click here to see answer by jim_thompson5910(28504)

Question 210093: -2x-18=6(1-2x)+4x

Click here to see answer by Earlsdon(6287)

Question 210185: Please help me understand (I don't have the text was copy given by teacher)
12 6 15 + /(divided)
write an expression equal to 13
Click here to see answer by Alan3354(30983)

Question 210213: how do you write the expression a number less than 35?
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Question 210275: Bob can groom a horse for a show in 2 hours. Eddie can do it in 1.5 hours. How long will it take to groom one horse if they work together?
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Question 210279: Solve each formula for the indicated variable: R(r1+r2)=r1r2,for R.
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Question 210203: at 310 feet, the millennium force roller coaster once was the tallest coaster in the world. write an expression to show the height of the current record holder. explain what the variable represents.
Click here to see answer by Alan3354(30983)

Question 210316: 0.4(x+0.7)=0.6(x-4.2) is the problem. I apply the distributive property and then get 0.4x+0.28=0.6x-2.52. I don't understand where to go from here to solve for x.
Click here to see answer by stanbon(57246)

Question 210326: 7-(-y-5)=2(y+3)-6(y+1)
Click here to see answer by HyperBrain(694)

Question 210386: 3(x-6)-4(3x+1)=x-22
Click here to see answer by tutor_paul(490)

Question 210474: solve for y
2y+18=12-6(y+7)
Click here to see answer by checkley77(12569)

Question 210515: 3xsquared- 12x=0 solve for x
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Question 210515: 3xsquared- 12x=0 solve for x
Click here to see answer by Edwin McCravy(8882)

Question 210540: 21+15
_____
3+6
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Question 210546: the total height of a 1-foot tall birdbath if it is placed on a base that is b feet tall
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Question 210520: what is twice the quotient of 50 and the sum of a number y and 8
Click here to see answer by Edwin McCravy(8882)

Question 210635: Please show me how to work these problems: Solve for x.
1. a(3tx-2b) = c(dx-2)
and
2. a-c/x-a = m
Click here to see answer by jim_thompson5910(28504)

Question 210649: how would i write the algebraic expression for this one:r squared+4r+7
Click here to see answer by Earlsdon(6287)

Question 210643: what is the answer to 999 less than 45 increased by the product of a number and 85?
Click here to see answer by Earlsdon(6287)

Question 210642: What is the answer to 3 times the difference of a number squared and 82?
Click here to see answer by Earlsdon(6287)

Question 210664: These are extra problems I need help to understand to bring up my grade please help I don't get it
Find the value for the given variable Show all steps and check answers showing all work. Not sure how to type in the problem.
a+1/6 = 2/a or a+1 over 6 = 2 over a
and
5/3x+1 = 3/3x-1 or 5 over 3x+1 = 3 over 3x-1

Click here to see answer by vleith(2825)

Question 210662: I am kind of lost on these problems please help
Solve find the value for the given variable Show all work and check answers showing all work
2x + 6 over 5 = x+4 over 3
3(2x+6) = 5(x+4)
6x +18 = 5x + 20 now I am confused and also don't know how to check answer

I would like to know if these are right and how to show the work to check answer
b/4 + b/3 = 7
12(b/4 + b/3) = 12(7)
12(b/4) + 12(b/3 = 84
3b + 4b = 84
7b = 84
b = 12

b/6 - b-2/8 = 4
LCD is 48
48(b/6 - b-2/8) = 48 (4)
48 (b/6 - 48 ( b-2/8) = 192
8b - 6(b-2) = 192
8b - 6b - 12 = 192
2b = 204
b = 102

Click here to see answer by vleith(2825)

Question 210774: f 0f g {3} when f=2x and g = 5x-1
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Question 210970: I am lost in trying to solve this:
Solve for x in terms of the other variables : d= m-1 divided by 2x

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Question 210987: Please let me know if my answer to this is correct. The problem is to factor numerator and simplify: 2ab+b^2 divided by b. I figured 2a+b but not sure if correct.
Click here to see answer by stanbon(57246)

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