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

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

Question 161149: A car radiator has a capacity of 16 quarts and is filled with a 25% antifreeze solution. How much must be drained off and replaced with pure antifreeze to obtain a 40% antifreeze solution?
Click here to see answer by nerdybill(6962)

Question 161135: I've been trying to think of a solution for this answer but stump. Our teacher didnt have enough time in class to elaborate on this part. So please help.
The problem is:
y = 2x - 7
y = -3x + 3
I already figure out that x = 2 but what is y?
Click here to see answer by Fombitz(13828)

Question 161309: Can you help me solve this variables with equations.
On my worksheet it says "Sometimes you need to rewrite an equation so that a variable is only on one side of the equation. To accomplish this, add the opposite of the term to both sides of the equation. Then add, subtract, multiply, or divide in order to isolate the variable."
It gave a few examples, but I can't seem to get the same format they are computing.
So this is the problem.
2x-1=4x+3 I got a -2 but I'm not so sure if its the correct answer. Please help me with this problem!! Thank you :)
Click here to see answer by stanbon(57387)

Question 161380: Hi,
Help much appreciated. I am trying to rearrange the logistic function p/1-p = x to give the result p = x/1+x but cannot see the steps needed to do this. Can someone show me?
Click here to see answer by ankor@dixie-net.com(15660)

Question 161389: Can you please help me with this problem? thank you!
Sometimes you need to rewrite an equation so that a variable is on only one side of the equation. To accomplish this, add the opposite of the term to both sides of the equation. Then add, subtract, multiply, or divide in order to isolate the variable.
3x-5=x-7
Thank you!
Click here to see answer by checkley77(12569)

Question 161381: CAN SOMEONE PLEASE HELP ME WITH THIS PROBLEM:
Solve the formula for the specified variable.d = rt for t

Click here to see answer by checkley77(12569)

Question 161427: how do you solve:
the length of a rectangle is 2 less than 4 times the width and the perimeter is 56?
Click here to see answer by checkley77(12569)

Question 161427: how do you solve:
the length of a rectangle is 2 less than 4 times the width and the perimeter is 56?
Click here to see answer by nerdybill(6962)

Question 161481: CAN SOMEONE PLEASE HELP ME WITH THIS PROBLEM PLEASE:
Find functions f and g so that h(x) = (f o g)(x).
h(x) = cube root (59x^2 + 78)
Click here to see answer by jim_thompson5910(28598)

Question 161732: Hi,i am not sure if this is the right section, but here is my problem anyway.
I am studying mechanics and i have been asked to do this for homework.
Telegraph poles, 40m apart stand alongside a straigh railway line. The times taken for a locomotive to pass the two gaps between three consecutive poles are 2.5 seconds and 2.3 seconds, respectively. Assume that the acceleration of the train is constant. Calculate the acceleration of the train and the speed past the first post.
Thanks in advance.
Click here to see answer by scott8148(6628)

Question 161821: how do u combine the terms of variable such as : x2+3+5y+y+5
Click here to see answer by Mariah24(4)

Question 161821: how do u combine the terms of variable such as : x2+3+5y+y+5
Click here to see answer by checkley77(12569)

Question 161820: how do u combine the terms of variable such as : x2+3+5y+y+5
Click here to see answer by checkley77(12569)

Question 161848: Bob is twice as old as Emma; Kent is 16 years older than Emma; the sum of their ages is 60 years; find the age of each.
Lets translate this into algebra
Your variables will be:
Bob = b
Emma= e
Kent= k
So
b = 2e
k = e + 16
b+e+k=60
you can only solve one equation if it only has one variable; so lets try to work with variable e only:
Since **b=2e and **k=e + 16
then by substitution
b+e+k=60
(2e)+e + (e+16)=60
4e+16=60
4e=44
e=11
Then b=2e=2(11)=22
k=e+16=11+16=27
check:
b+e+k=11+22+37=60

Click here to see answer by eperette(173)

Question 161846: Hi, I was wondering how to simplify expressions with the distributive property. In addition, here are some problems I need help simplifying with:
problem number one: 3y-(6y+2)(-y)
problem number two:(-7x+x^2)(-x)+x^2
problem number three: (c+3c^2) (-c^2)
I need help, because I don't know how to simplify these problems! Thanks in advance.
Click here to see answer by checkley77(12569)

Question 161866: use the equation 2(2-y)=3x what are the values of y, when x= -4, 0, 2/3, and 3?
Click here to see answer by Alan3354(30993)

Question 161866: use the equation 2(2-y)=3x what are the values of y, when x= -4, 0, 2/3, and 3?
Click here to see answer by checkley77(12569)

Question 161813: Were do i find a question like this: 6x+(5x-8)
Click here to see answer by elima(1433)

Question 161877: please help
find the value of y if 13.56y-14.76=3(4.12y-6.72)
Click here to see answer by checkley77(12569)

Question 161903: ad=f;a

Click here to see answer by checkley77(12569)

Question 161875: please help me !! please and thanks
1/3(27x+18)=12+6(x-4)
solve thank you
Click here to see answer by checkley77(12569)

Question 161875: please help me !! please and thanks
1/3(27x+18)=12+6(x-4)
solve thank you
Click here to see answer by scott8148(6628)

Question 161910: 2. Consider the equation a/4 = 20 - a/6
a. Multiply each side by 12 and solve the resulting equation.
B. Multiply each side by 24 and solve the resulting equation.
c. What conclusions can you make from your work in parts a and b?
If you can show me the process of writing all the steps to solving this kind of equation that would be great. I have a way in my book i just can't understand it. Cause i dont learn by reading i learn from doing.
Thanks
Click here to see answer by checkley77(12569)

Question 161926: Could you please help me solve the following problem. Each time I try, the exponents cancel themselves out and I get zero equalling a number. Thanks.
3(Q-2) + 2 = 5Q - 7 - 2Q
Click here to see answer by checkley77(12569)

Question 161920: 6-(-5)=5r-3
Click here to see answer by jim_thompson5910(28598)

Question 162001: The intensity (I) of light is inversely proportional to the distance (D) from the light squared. Write an equation for this phenomenon.
Click here to see answer by Earlsdon(6287)

Question 162042: A plane flies x mph. How far can it go in y hours?
(x miles/hour)(y hours)
xy miles

Click here to see answer by eperette(173)

Question 162045: If a pipe can fill a tank in x hours, what fractional part of the tank will be filled in one hour?
Click here to see answer by Edwin McCravy(8909)

Question 162044: The width of a rectangle is y feet long, and it is 4 feet longer than it is wide. What is the area of the rectangle?
Click here to see answer by schrammbledeggs(41)

Question 161134: 3 less than the quotient of a number and 5
Click here to see answer by 9j84(1)

Question 162150: 36. S = 2 * pie * r^2 + 2 * pie * r * h
find for h
Click here to see answer by ankor@dixie-net.com(15660)

Question 162204: A taxicab company charges $2.10 for the first mile plus $0.80 per mile after the first mile. Carmen pays $11.70 total. What is the number of miles Carmen traveled? Please show me how to set up the equation! Thanks!
Click here to see answer by checkley77(12569)

Question 162180: The length of a rectangle is twice the width. The perimeter is 84cm more than the width. Make a diagram and find the rectangle's dimensions.
Click here to see answer by KnightOwlTutor(293)

Question 162255: subtract:4a-7ab+3b+12 from 12a-9ab+5b-3
Click here to see answer by tutor_paul(490)

Question 162341: 2(8y-7)= 2(3+8y)
Click here to see answer by checkley77(12569)

Question 162370: please help me!
solve for the indicated variable
C=2~--(pie)r, solve for r

Click here to see answer by Alan3354(30993)

Question 162372: solve for the indicated variable
S=B+1/2Pc
solve for c

please and thanks
Click here to see answer by Alan3354(30993)

Question 162378: rewrite
3x+4y=15+6y
so that y is a function of x

please help me understand for my test!
Click here to see answer by Alan3354(30993)

Question 162417: -3x+2y=11
3x-4y=-19
use addition method
solve for x and y to get coordinate
Click here to see answer by stanbon(57387)

Question 162467: I'm not sure if this is the right section, but I need help.
Use synthetic division to find (2x^3-5x^2+7X-1)/(x-1)
I came up with 2x^2-3x+4
Can you please tell me if i did this right?
Thanks
Click here to see answer by checkley77(12569)

Question 162510: I need to use "LEWAC" to answer this.
Phil is 24 years older than Stanley. Four years ago, he was 7 times as old as Stanley then. Find their present ages.
Click here to see answer by josmiceli(9697)

Question 162641: Direct variation or inverse variation?
Please help. I don't understand how to tell variations apart.
y=3x
Click here to see answer by KnightOwlTutor(293)

Question 162640: What kind of variation is this?
Area of a circle=PI(radius)^2
Click here to see answer by KnightOwlTutor(293)

Older solutions: 1..45, 46..90, 91..135, 136..180, 181..225, 226..270, 271..315, 316..360, 361..405, 406..450, 451..495, 496..540, 541..585, 586..630, 631..675, 676..720, 721..765, 766..810, 811..855, 856..900, 901..945, 946..990, 991..1035, 1036..1080, 1081..1125, 1126..1170, 1171..1215, 1216..1260, 1261..1305, 1306..1350, 1351..1395, 1396..1440, 1441..1485, 1486..1530, 1531..1575, 1576..1620, 1621..1665, 1666..1710, 1711..1755, 1756..1800, 1801..1845, 1846..1890, 1891..1935, 1936..1980, 1981..2025, 2026..2070, 2071..2115, 2116..2160, 2161..2205, 2206..2250, 2251..2295, 2296..2340, 2341..2385, 2386..2430, 2431..2475, 2476..2520, 2521..2565, 2566..2610, 2611..2655, 2656..2700, 2701..2745, 2746..2790, 2791..2835, 2836..2880, 2881..2925, 2926..2970, 2971..3015, 3016..3060, 3061..3105, 3106..3150, 3151..3195, 3196..3240, 3241..3285, 3286..3330, 3331..3375, 3376..3420, 3421..3465, 3466..3510, 3511..3555, 3556..3600, 3601..3645, 3646..3690, 3691..3735, 3736..3780, 3781..3825, 3826..3870, 3871..3915, 3916..3960, 3961..4005, 4006..4050, 4051..4095, 4096..4140, 4141..4185, 4186..4230, 4231..4275, 4276..4320, 4321..4365, 4366..4410, 4411..4455, 4456..4500, 4501..4545, 4546..4590, 4591..4635, 4636..4680, 4681..4725, 4726..4770, 4771..4815, 4816..4860, 4861..4905, 4906..4950, 4951..4995, 4996..5040, 5041..5085, 5086..5130, 5131..5175, 5176..5220, 5221..5265, 5266..5310, 5311..5355, 5356..5400, 5401..5445, 5446..5490, 5491..5535, 5536..5580, 5581..5625, 5626..5670, 5671..5715, 5716..5760, 5761..5805, 5806..5850, 5851..5895, 5896..5940, 5941..5985, 5986..6030, 6031..6075, 6076..6120, 6121..6165, 6166..6210, 6211..6255, 6256..6300, 6301..6345, 6346..6390, 6391..6435, 6436..6480, 6481..6525, 6526..6570, 6571..6615, 6616..6660, 6661..6705, 6706..6750, 6751..6795, 6796..6840, 6841..6885, 6886..6930, 6931..6975, 6976..7020, 7021..7065, 7066..7110, 7111..7155, 7156..7200, 7201..7245, 7246..7290, 7291..7335, 7336..7380, 7381..7425, 7426..7470, 7471..7515, 7516..7560, 7561..7605, 7606..7650, 7651..7695, 7696..7740, 7741..7785, 7786..7830, 7831..7875, 7876..7920, 7921..7965, 7966..8010, 8011..8055, 8056..8100, 8101..8145, 8146..8190, 8191..8235, 8236..8280, 8281..8325, 8326..8370, 8371..8415, 8416..8460, 8461..8505, 8506..8550, 8551..8595, 8596..8640, 8641..8685, 8686..8730, 8731..8775, 8776..8820, 8821..8865, 8866..8910, 8911..8955, 8956..9000, 9001..9045, 9046..9090, 9091..9135, 9136..9180, 9181..9225, 9226..9270, 9271..9315, 9316..9360, 9361..9405, 9406..9450, 9451..9495, 9496..9540, 9541..9585, 9586..9630, 9631..9675, 9676..9720, 9721..9765, 9766..9810, 9811..9855, 9856..9900, 9901..9945, 9946..9990, 9991..10035, 10036..10080, 10081..10125, 10126..10170, 10171..10215, 10216..10260, 10261..10305, 10306..10350, 10351..10395, 10396..10440, 10441..10485, 10486..10530, 10531..10575, 10576..10620, 10621..10665, 10666..10710, 10711..10755, 10756..10800