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

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

Question 524711: My homework is Adding and Subtracting Expressions. I have this problem on my homework 8x + 5x and I put 13. I don't know do they what the answer to the poblem or just tell them what x is? I'm so lost on this.
Click here to see answer by mananth(12270)

Question 524782: multiply or divide as indicated
y^2-16/y^3-64 ÷ y^2-3y-18/y^2+5y+6

Click here to see answer by bucky(2189)

Question 525107: how do you substitute? the equation is
x=2y-3
4x-5y=-3
i dont understand how to dp this???

Click here to see answer by Tatiana_Stebko(1326)

Question 525291: Please help!
One of the brightest stars in the sky is Procyon, which is part of the constellation cans minor. Procyon is 11 light years from earth. one light year= 5.88 x 10^12. How far in miles is procyon. Write answer in scientific notation.

Click here to see answer by solver91311(16897)

Question 525470: 56 - 8p = 14
Click here to see answer by jim_thompson5910(28595)

Question 525503: What is 'n' in this expression? : n-10= 5/6n-7-2/6n
(5/6n and 2/6n are both in fraction form)
I tried every way I can think of to solve this, and I just can't get it! I really need help, quick! In my Algebra book, it says that the answer is 5, but I always get 11 1/3. I even 'checked' the books answer, and it turned out correct! Thank You so much!
Click here to see answer by jim_thompson5910(28595)

Question 525920: 2x-3y=-24
x+6y=18

Click here to see answer by oberobic(2304)

Question 526528: Simplify (7ab)^2
it means square of 7ab =7*7*a*a*b*b=49a2b2

Click here to see answer by ogunsola(1)

Question 526619: Find the height of a cylinder with volume 2500pi feet and radius 10 feet
Click here to see answer by rfer(12662)

Question 526627: The sales representative informs you that there are 56 houses for sale with two floor plans still available. Use x to represent floor plan one and y to represent floor plan two. Write an equation that illustrates the situation
Click here to see answer by stanbon(57377)

Question 526668: from my previous exam question that I cant figure out.
dunno if this question has anything to do with it
> A cuboidal container has a height of "h" meter, a width of (h+3) meters and a >length of (2h +1) meters.
>
>Expand and Fully simplify h(2h+1)(h+3).
here's the question I don't understand
"The volume of a box in cubic meters is 20 times the height in meters (V=20"h" m^3) "
the answer to the question is
2h^3 + 7h^3 - 17h = 0
h = 0, 1.65, -5.15 hence 1.65m
i have no idea how this answer came to be, if you could please help me that would be great. thanks

Click here to see answer by KMST(1868)

Question 526651: After a sailboat had been on the water for 3 hours, a change in the wind direction reduced the average speed of the boat by 7 mph. The entire distance sailed was 51 miles. The total time spent sailing was 5 hours. How far did the sailboat travel in the first 3 hours?
Click here to see answer by ankor@dixie-net.com(15657)

Question 526905: Please help me answer this equation!
5x-3(5-2x) = -15
I need to figure out what the variable "x" is.
I can't get it because I'm having problems with the integers.
Please help!
Click here to see answer by Alan3354(30993)

Question 527078: y=mx+b solve for m
Click here to see answer by oberobic(2304)

Question 527959: ten more than three times the number is 130.
Click here to see answer by jim_thompson5910(28595)

Question 528446: Solve for v.
t-v/r=k
Click here to see answer by jim_thompson5910(28595)

Question 528427: What are some phrases for multiplying variables? Example: six times a number.
Click here to see answer by jim_thompson5910(28595)

Question 528524: I'm trying to solve for x, coming up with no solution and want to verify it is correct. 3/x + 9/2x = 1
Click here to see answer by Alan3354(30993)

Question 528792: Give an example of a rational function that is undefined at x = a where a is a real number. Next, state the domain of your rational function using both set notation and interval notation
Click here to see answer by jim_thompson5910(28595)

Question 528884: Please help!!!!
Translate the English phrase into a variable expression: The product of 7 and the total of x and 4

Click here to see answer by solver91311(16897)

Question 528889: Please help!!!!
Find slope of line that passes through the points (2, -5) and (3,4)
Click here to see answer by solver91311(16897)

Question 528940: Please help me solve this equation:
The sum of four positive integers is 68. The product of the same four integers is 50141. The sum of the squares of the same four integers is 1420. What are the values of the four positive integers?
a+b+c+d=68
axbxcxd=50141
a^2+b^2+c^2+d^2=1420
Click here to see answer by Alan3354(30993)

Question 529203: can you please explain how to solve this problem.I'm trying to help my 5th grader understand. thanks=)
8+n if n=12,and 7xn if n=8
Click here to see answer by josmiceli(9686)

Question 529268: #1 Would "m" plus 5 be written: m+5 ?
#2 A letter right next to a number signifies multiplication, correct? (i.e. "3m")
Thanks so much!!
Click here to see answer by KMST(1868)

Question 529383: 1. The cost, in millions of dollars, to remove x % of pollution in a lake modeled by
a. What is the cost to remove 75% of the pollutant?
b. What is the cost to remove 90% of the pollutant?
c. What is the cost to remove 99% of the pollutant?
d. For what value is this equation undefined?
e. Do the answers to sections a. through d. match your expectations? Explain why or why not.

Click here to see answer by richard1234(5390)

Question 529532: 23>u+8

Click here to see answer by MathLover1(6634)

Question 529648: My question is whats substition I keep hearing about? How does it work? Can you tell me how to solve a problem using substition?
Click here to see answer by josmiceli(9686)

Question 529630: -0.2x squared+80x-6000 factor the expression
Click here to see answer by ankor@dixie-net.com(15657)

Question 529735: The problem I have is: Write an equation for the vertical line that contains
A(6, -9). I am trying to help my daughter with her homework and don't remember how to do this.
Thank you!!!
Click here to see answer by solver91311(16897)

Question 529790: 7x+6y=30
9x-8y=15
I need to find x & y using Elimination.
Thank You~
Click here to see answer by jim_thompson5910(28595)

Question 529790: 7x+6y=30
9x-8y=15
I need to find x & y using Elimination.
Thank You~
Click here to see answer by josmiceli(9686)

Question 529990: (7+2x) (7-2x)=
Click here to see answer by josmiceli(9686)

Question 530003: what is the equation of the function for a parabola that moves 3 units to the left of the origin,8 units down from the origin, is flipped over the x-axis, and is stretched vertically five times as much as the basic f(x)=x^2
Click here to see answer by Edwin McCravy(8909)

Question 530117: Use the distributive property to rewrite each expression. then simplify
here is the problem~ (5y-3)7
Click here to see answer by stanbon(57377)

Question 530117: Use the distributive property to rewrite each expression. then simplify
here is the problem~ (5y-3)7
Click here to see answer by Math_prodigy(21)

Question 530205: what is the slope of the line parallel to this, y = -4/3x - 9
Click here to see answer by jim_thompson5910(28595)

Question 530227: Patsy can do 1/4 of a work in 10 days. Quincy can do 40% of the work in 15 days and Rhonda can do 1/3 of the work in 13 days. Who will complete the work first?
Click here to see answer by Edwin McCravy(8909)

Question 530315: Hi!
I'm not really sure I understand this problem and I'm having problems formulating a solution. There's an attempt below which should be correct but I think my method is ambiguous. A better method would be appreciated and any other help too!
Paul worked 7 more problems than Jean. Together they worked 55 problems. How many did each boy work?

Paul worked 7 more than Jean therefore problems for Paul
Click here to see answer by Earlsdon(6287)

Question 530431: 8-(3+b)=b-9
Click here to see answer by rfer(12662)

Question 531212: 2(2x+5/3x)^2 -5 = 9(2x+5/3x)
This problem is supposed to be solved by substituting a variable like U for (2x+5/3x).Write in standard form. (2U^2 -9U -5=0) Factor. (2U+1)(U-5). Set to zero. U=-1/2 and U=5. But, when I try to set these values to (2x+5/3x)to solve for x, the answers don't fit into the original equation as they should. What in the world is wrong? Thanks so much for your help.
Click here to see answer by stanbon(57377)

Question 531390: how do you solve:
1/5w = 2
Click here to see answer by Alan3354(30993)

Question 531417: (3a-2b)(3a+2b)
Click here to see answer by chiga89(2)

Question 531601: How can I Find the Values for the Variables?
x^2 + 16x +48 = o ?
Thank YOU
Click here to see answer by oberobic(2304)

Question 531601: How can I Find the Values for the Variables?
x^2 + 16x +48 = o ?
Thank YOU
Click here to see answer by stanbon(57377)

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