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

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 Question 120940: s=n/2(a+L); for L please show me how to solve this step by step.. thank you Click here to see answer by edjones(7794)

 Question 121022: Please help me understand . The equation is : ( a^-1 + b^-1)^2 . I need to simplify it. The answer is (b^2+2ab+a^2)/a^2*b^2. Can you explain why. Why after using a common denominator , the " 2ab" is out of the fraction? Thank you . Viktor Click here to see answer by nabla(475)

 Question 121082: I am really having trouble with this problem. I do not understand what to do. I hope I am posting this in the correct place. Thank you far any help you can give. A car rents for \$40.per day plus 18 cents per mile. You are on a daily budget of \$67.per day. What milage will allow you to stay within your budget? Thank you again. Click here to see answer by solver91311(18785)

 Question 121006: I have know Idea what I am doing.I am trying to learn how to multiply and write in scientific notation. I have 3 problems I need to learn how to do. (8.3*10to the negative 5th)(2*10^12)= (7*10to the neg 3rd)(2.5*10^3)= and (2.1*10tothe neg8th)(2.5*10^3)= Click here to see answer by scott8148(6628)

 Question 121220: 2K+5d=3d-4 What does K equal? -4(3a+c)=b What does a equal? 3m-5(m+t)=7(t+q) What does m equal? Click here to see answer by jim_thompson5910(29613)

 Question 121375: Find the solution to system of equations by substitution. Problem: Y=2X+7 and Y=-X-5. I am confused on which equation do i insert and when. For this problem I tried Y=-X(2X+7)-5, Then I'm stumped, I think the -x multiplied by the 2x is messing me up. Plus both of these start with Y=. The other examples problems show x+2y=6 and 4y=12-2x ? Totally different. Can you help me sort out how to do substition? How to start. I have went thru example after example in book and I keep getting the wrong answers I am missing a step or concept i think. Click here to see answer by checkley71(8403)

 Question 121438: Adult tickets for a play cost \$17 and child tickets cost \$2. If there were 22 people at a performance and the theater collected \$179 from ticket sales, how many adults and how many children attended the play? Click here to see answer by stanbon(60771)

 Question 121439: A small company produces both standard and deluxe playhouses. The standard playhouses take 12 hours of labor to produce, and the deluxe playhouses take 20 hours. The labor available is limited to 800 hours per week, and the total production capacity is 50 items per week. Existing orders require the company to produce at least 10 standard playhouses and 15 deluxe playhouses per week. Write a system of inequalities representing this situation, where x is the number of standard playhouses and y is the number of deluxe playhouses. Then graph the system of inequalities. Click here to see answer by ankor@dixie-net.com(16524)

 Question 121579: in 2001 18.2 milion households had a dvd player. If theis population grows at 25% annually, how many households will have a dvd player in 2006 ( 5 years later)? a = p(1+r) to the t power Click here to see answer by checkley71(8403)

 Question 121450: The length of a rectangle is 1 in. more than twice its width. If the perimeter of the rectangle is 32 in., find the width of the rectangle. Click here to see answer by checkley71(8403)

 Question 121688: The bill for five glasses of apple juice and four salads is \$9.50, but the bill for four glasses of apple juice and five salads is \$10.30. What would be the bill for a glass of juice and a salad? Click here to see answer by jainenderkapoor(61)

 Question 121692: Substitition- x + y = 13 y - x = -7 Click here to see answer by Nellene Mae(3)
 Question 121692: Substitition- x + y = 13 y - x = -7 Click here to see answer by Fombitz(13828)

 Question 122020: Dick is now seven times as old as Harry. In six years Dick will be five times as old as Harry. How old will Harry be in 5 years? Click here to see answer by ankor@dixie-net.com(16524)

 Question 122019: Find three consecutive odd integers such that the sum of the largest and twice the smallest is 25. Click here to see answer by checkley71(8403)

 Question 122017: The larger of two consecutive intergers is 7 greater than twice the smaller. Find the integers. The intergers are _____ and _____. Click here to see answer by checkley71(8403)

 Question 122015: The larger of two consecutive intergers is 7 greater than twice the smaller. Find the integers. The intergers are _____ and _____. Click here to see answer by checkley71(8403)

 Question 122150: I think this is the right section. My father in law is trying to help someone with their homework and called me. My algebra memory has faded :) solve for x x=zb-zk^2 (or, in english, x equals zb minus zk squared) Click here to see answer by jim_thompson5910(29613)

 Question 122170: Find the sum of two consecutive postive odd integers whose produce is 143 Click here to see answer by tutor_paul(493)

 Question 122344: Mr. Sheehan was cleaning his room when he discovered a bunch of coins under the bed. He found 20 nickles and dimes totaling \$2.60. How man of each kind did Mr. Sheehan find? How do we set this up? How do we solve for two unknown variables when all we have is a value? Click here to see answer by solver91311(18785)

 Question 122905: The directions says solve the problems using subsitution. I need help solving y=x+4 y=3x. Click here to see answer by checkley71(8403)

 Question 122957: My daughter and I have been working on this one problem for an hour, we know the answer, but do not know how to get the answer, here it is y+3x=1 2y+5x=5 Click here to see answer by scott8148(6628)

 Question 123061: sorry i cant seem to figure this one out SOLVE FOR X 0.1x-0.01(10-x)+0.01(100-x)=19 Thanks ALOT Click here to see answer by checkley71(8403)

 Question 123062: Sorry I cant seem to figure this out SOLVE FOR X 0.4x+0.24(x-5)=0.08 THANKS ALOT, VERY MUCH APPRECIATED Click here to see answer by stanbon(60771)

 Question 123064: sorry i cant seem to figure this one out SOLVE FOR X 0.05x+0.065(5000-x)=295 THANKS ALOT Click here to see answer by checkley71(8403)

 Question 123139: Be certain you have solved for both variables in the system of equations. Solve the following systems of equations algebraically. Show your work. 5x-y=-5 3x-5y=-3 Click here to see answer by MathLover1(7480)

 Question 123232: My question is can you help me solve this equation? This problem is a Substition. x+2y=13 3x-5y=6 I do not understand how to find x and y for this equation. If you could help it would be great. Thank you. Click here to see answer by solver91311(18785)