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

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 Algebra: Expressions involving variables, substitution Solvers Lessons Answers archive Quiz In Depth

 Question 90614: A manufacturer has determined that the revenue received from selling x items of a product is given by R(x) = -0.3x2 + 200x and the cost to produce x items of the product is given by C(x) = 80x + 9400. Assuming that all of the products produced can be sold, how many should be produced to maximize the profit? (Hint: profit = revenue - cost) I have such a hard time with word problems. I reall appreciate the help Click here to see answer by scott8148(6628)

 Question 90857: The cost C in dollars to remove p% of the pollution in a small pond near a factory is given by C(p) = 5000p/100-p, 0<-p<100 , Find the cost of removing 75% of the pollution. Click here to see answer by stanbon(57412)

 Question 91114: A car radiator has a capacity of 16 quarts and is filled with a 25% Anti-freeze solution. How much must be drained off and replaced with pure Anti-freeze to obtain a 40% Anti-freeze solution? Click here to see answer by ankor@dixie-net.com(15661)

 Question 91698: write the expression for each quantity 1. the value in cents of 5 quarters 2. the value in cents of q quarters 3.the number of months in 7 years 4. the number of monthes in y years 5. the number of gallons in 21 quarts 6.the number of gallons in q quarts ? i dont get it ? plz help Click here to see answer by scott8148(6628)

 Question 91750: 3w-13=1/4(52-12w) 3w-13=13-3w First, i know i have to distribute 1/4 to 52 and -12w. Then, i'm stuck, i know that the answer is 4 1/3 but i don't know how to get that answer. PLEASE HELPP! Click here to see answer by stanbon(57412)

 Question 91867: I have this assignment and my calcualtor doesn't evaluate logarithisms and exponents. And I can't find the formula to write the expression In x = 4 in exponential notation. Click here to see answer by homeworkhelpanytime(21)

 Question 91999: add rational expressions with common denominator 3y-3x/5y - 4y+8x/5y Thank you so very much for the help Click here to see answer by homeworkhelpanytime(21)

 Question 91888: Our galaxy is estimated to be 5.6 x 10^19 mi across. How long (in hours) would it take a spaceship to cross the galaxy traveling at 37,500 mph. Click here to see answer by ankor@dixie-net.com(15661)

 Question 92171: Translate and simplify: "quantity three less than twice the sum of a number and 5". Click here to see answer by stanbon(57412)

 Question 92213: A.) Linear Growth A town has a fixed increase in population growth number of population increase each year. population 1897. Find the growth rates for the following I don't get this at all? Year (t) Population (P) t = 0 Po = 1897 (2010) t = 1 (2011) t = 2 (2012) t = 3 (2013) t = 6 (2016) B.) Find a linear equation in the form P = mt + b (y = mx + b), which gives the population, P, t years from 2010. Click here to see answer by bucky(2189)

 Question 92113: I'm suppose to make a table showing the value of each expression when the value of the variable is 1,2,3,4,and 5. I don't understand how I'm suppose to do that? Click here to see answer by checkley71(8403)

 Question 92269: The problem is 3x^2 - 10x = 8 I got x = 6 as shown below except when I plug it in it doesn't work. 3x^2/x = 10x+8/x 3x = 18 x = 6 Click here to see answer by checkley71(8403)

 Question 92333: solve the system by substitution x + y = 12 -x + y = 2 Click here to see answer by jim_thompson5910(28598)

 Question 92393: a number to the second power is called squared and one to the third power is called cubed. what is it called to the 4th and 5th power? Click here to see answer by stanbon(57412)

 Question 92739: Are there any values of the variable a for which the expressions 2+a and 2a have the same value? Explain. Click here to see answer by jim_thompson5910(28598)

 Question 92748: This might be a stupid question but, it's bothering me so here it is: Evaluate the expression for the given value of x : x=-1 I'm not sure if I'm supposed to put the -1 in parentheses because if I do I get a different answer. Look: or --1^2+-1-1=-1 Which is it? Click here to see answer by bucky(2189)

 Question 92820: If 2r = 5s and 5s = 6t, what does r equal in terms of t? Click here to see answer by checkley75(3666)

 Question 92918: Hey this is Debbie and I am having trouble understanding this. For these linear functions complete the table of values by substitution. b=a+3 a 0 1 2 3 4 5 10 b I am having trouble working how to do substitution because I forgot how to do it.Must help appreciated. Click here to see answer by scott8148(6628)

 Question 92952: Solve for y. x + 3y = 12 Click here to see answer by jim_thompson5910(28598)

 Question 93097: Simplify the expression. Assume that the vaiables in the denominator are non-zero. (4/xy^2) -3 This is hard to type but it looked like a fraction in big parenthesis as 4 over xy to the -3 power. Thanks so much!! Click here to see answer by tutorcecilia(2152)

 Question 93242: 1. The value in cents of 5 quarters Click here to see answer by Nate(3500)

 Question 93319: Can you help me with this problem? Solve for x. x+2y= -1 3x-4y= 27 I think I am supposed to solve for y in one problem, then substitute it in the next one... but I'm not sure. Thanks in advance!!! Click here to see answer by stanbon(57412)
 Question 93319: Can you help me with this problem? Solve for x. x+2y= -1 3x-4y= 27 I think I am supposed to solve for y in one problem, then substitute it in the next one... but I'm not sure. Thanks in advance!!! Click here to see answer by jim_thompson5910(28598)

 Question 93314: Can you please help me with this problem? Solve for x. x+2y= -1 3x-4y= 27 I think I am supposed to solve for the y variable in one problem, then plug it in for the next one. I'm not sure though. Thank you in advance!!! Click here to see answer by checkley75(3666)

 Question 93320: I NEED HELP ON THIS PROBLEM. I DON'T UNDERSTAND HOW TO FIGURE IT OUT. THANKS Click here to see answer by ankor@dixie-net.com(15661)