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

Tutors Answer Your Questions about Expressions-with-variables (FREE)

Question 416785: How do you solve for x in this equation?
7.78 = 20 * ( x / 3.50)
Click here to see answer by Tatiana_Stebko(1326)

Question 417289: Super unleaded gasoline costs 9 cents more per gallon than regular unleaded gasoline. A service station buys 3,000 gallons of super unleaded and 2,000 gallons of regular unleaded for $8,919. What is the cost per gallon of each kind of gasoline?
Click here to see answer by mananth(12270)

Question 417477: I have a total sales number that includes tax of 7.75%. The number is $3,618,214.77. How do I determine the amount of tax the is included in the number?
.0775x=$3,618,214.77-x ?
Click here to see answer by josmiceli(9649)

Question 417485: Ok, here it is: Select a variable to represent one quantity and state what the variable represents. Then express the other quantities in terms of the variable selected. Translate the problem into an equation and then solve.
* The sum of two numbers is 135. Find the two numbers if the larger one is 9 less than twice the smaller?
I got to this point: smaller = x
larger = 2x-9
Now I need help with the rest.

Click here to see answer by sudhanshu_kmr(1152)

Question 417510: Could someone please show me how to solve this problem?
Multiply
-8(z-10)
Click here to see answer by stanbon(57219)

Question 417573: another problem I dont get. Dont understand this at all teacher says this is the problem and solution>
x+y=5
-2x-2y=-10
0=0
Click here to see answer by Gogonati(809)

Question 417641: what is the value of x in the equation:
x-1/4 = 5/x+7
Click here to see answer by jim_thompson5910(28476)

Question 417429: Im not sure if I've put this into the right catagory but heres the question:
Given that: a(3x + 2) + b(4x - 5) = 34x - 31
Work out the values of a and b.
Thankyou :)
Click here to see answer by ankor@dixie-net.com(15624)

Question 417768: Could someone please help me? Collect like terms
18/18x +7/18y - 7/18y + 10/18 y ( the letters are in the center of the fractions)
2. remove parentheses and simplify
8p + 4q - 8(8p - 5q + 4r)
Click here to see answer by stanbon(57219)

Question 417787: x+y+z=-9, 2x+4y+2z=-14, -x+6y-32=35 find solution _,_,_

Click here to see answer by MathLover1(6614)

Question 418041: simplify p^100/p^2
Click here to see answer by ewatrrr(10682)

Question 418186: Solve by the substitution method. What is the solution of the system?
7x+3y= -35
-7x+y=63

Click here to see answer by sudhanshu_kmr(1152)

Question 418186: Solve by the substitution method. What is the solution of the system?
7x+3y= -35
-7x+y=63

Click here to see answer by ewatrrr(10682)

Question 418741: Could someone please help me to solve and show me how to do this equation?
-8x-20=25 and 1/3
Click here to see answer by Alan3354(30959)

Question 418962: How do I do this? The difference of nineteen plus a number divided by five. Simplify if possible. I could not find an actual topic for this. Thanks
Click here to see answer by stanbon(57219)

Question 419021: find the value of the expression?
n+37 if n is 16?
Click here to see answer by richard1234(5390)

Question 419270: need help solving the following algebraic equation for n: 5n-15=85 ?
does n=95 ?
Click here to see answer by nerdybill(6948)

Question 419270: need help solving the following algebraic equation for n: 5n-15=85 ?
does n=95 ?
Click here to see answer by duckness73(43)

Question 419286: i need help solving the equation: d+e-15, if d is 12 and e is 5?
is it = 2 ?
Click here to see answer by duckness73(43)

Question 419278: i need help i dont know if am right am trying to solve the equation: d+e-15, if d is 12 and e is 5 ?
is the answer = 2 ?
Click here to see answer by jim_thompson5910(28476)

Question 418611: If operation 'o' is unknown and, a 'o' b = a + 2b ; and, 3 'o' X = 4 ; what is variable X?
I would just like the first steps to solving this equation because it's been a while since I've done any math work. I took a placement test a week ago, and this question came up. I was kinda stumped. I've racked my brain ever since then to remember some formula to help me out but I can't seem to come up with one.
Click here to see answer by ankor@dixie-net.com(15624)

Question 419504: Please help me with this question. We are learning about percentages and this question is confusing to me.
I have tried using the order of operations but keep getting stuck.
x% = 2x + 1/300 (2x +1 is the entire numerator in the fraction over 300)

Thanks!
Click here to see answer by sudhanshu_kmr(1152)

Question 420084: 220/m=4
Click here to see answer by stanbon(57219)

Question 420073: How do you find the zeros of f(x)=x(x-3)^2(x+2)and the multiplicity of each?
Click here to see answer by robertb(4012)

Question 420134: Find the polynomial function of degree three with rational coefficients and some of its zeroes are -2 and 1+i. Show work.
Click here to see answer by robertb(4012)

Question 420171: Use synthetic division to find P(3) for P(x)= -3x^2+6x-5. Show all work please
Click here to see answer by stanbon(57219)

Question 420653: solve for the variable in each equation below. show all work. check answer. if a solution is undefined, state that in answer.
10/x-6=5
Click here to see answer by stanbon(57219)

Question 420654: solve for the variable in each equation below. show all work. check answer. if a solution is undefined, state that in answer.
3/a+1=5/a+7
please help if you can. thanks
Click here to see answer by stanbon(57219)

Question 420684: 15c-10d
Click here to see answer by rfadrogane(214)

Question 420810: solve 6x-3y=5
x+2y=0
Click here to see answer by mananth(12270)

Question 420813: Use a graphing calculator to solve the following equation for x.
2^x=29
What is the solution set?
(Simplify your answer. Type an integer or a decimal rounded to the nearest thousandth.)

Click here to see answer by stanbon(57219)

Question 421091: barry is 8 years older than his sister. in 3 years he will be twice as old as sue was 5 years ago. find their ages now.
Click here to see answer by algebrahouse.com(1079)

Question 421223: You must buy 100 chickens for exactly $100. You must buy at least one chicken from each store. The first store charges 5 cents/chicken, the second charges $1/chicken and the third charges $5/chicken. How many chickens should you buy from each store? I know the answer is 80 for .05, 19 for $1, and 1 for$5. Is there any mathematical equation you can apply to solve it though, because I just used guess and check.
Click here to see answer by Edwin McCravy(8880)

Question 421425: -48/(7-9)^3 -2[1-5(2-6)+3^2]
Click here to see answer by stanbon(57219)

Question 421458: George is 6 times as old as Bobby. The sum of their ages is 98. How old is each now?
Click here to see answer by algebrahouse.com(1079)

Question 421459: The sum of Carl's and Patricia's ages is 30. Thirteen years ago, Patricia was three times as old as Carl. How old is each now?
Click here to see answer by robertb(4012)

Question 421525: moolah has 24 coins that are all dimes and quarters. the value of the coins is $3.75. how many dimes and how many quarters does moolah have?
Click here to see answer by josmiceli(9649)

Question 421736: "ten less than a certain veriable, m"
Click here to see answer by Gogonati(809)

Question 421737: how do i write ten less than a certain variable, m
Click here to see answer by rfer(12644)

Question 421800: The sum of the angles of a triangle is 180 degrees. If one angle of a triangle is ten degrees larger than the smallest angle and the third angle is 10 degrees more than twice the smallest angle, find the measures of the three angles? Please I need this in detail, step by step. :)
Click here to see answer by stanbon(57219)

Question 421802: An ice hockey rink is a rectangle with a perimeter of 174 meters. The length is 9 meters more than twice the width. Find the length and width?
Click here to see answer by stanbon(57219)

Question 421830: -4x-2y=-8 y=-2x+4
Click here to see answer by mananth(12270)

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