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

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

Question 45638: substitution method
y=13-3x
2x+9y=-8
Click here to see answer by mszlmb(115)

Question 46374: (question 1) Added to 5X+7Y-19Z to get 7X-7Y-15Z?
(question 2) what must be substracted from 3A+4b2-5C to give 2A+3b2+5c
Click here to see answer by AnlytcPhil(1278)

Question 46437: Hello, I want to make sure we got this right:
Question: which expression represents the sum of the oppoiste of a n umber and -12?
Answers:
a) -n = -12
b) -n + -12
c) -n(-12)
d) -n - (12)
we chose b) because the question uses the word SUM. Is that correct?
Thank you!
Click here to see answer by adamchapman(301)

Question 46560: I need help solving this equation without simplying
8y/8y*9y^2/5y
thank you
Click here to see answer by tutorcecilia(2152)

Question 46573: Perform the indicated operation and expression lowest terms. I really need help!

Click here to see answer by Earlsdon(6294)

Question 46551: the electrical resistance R of a wire varies directly as its length L and inversely as the square of its diameter. A wire 20 meters long and 0.6 centimeters in diameter made from a certain alloy has a resistance of 36ohms. What is the resistance of a piece of wire 60 meters long and 1.2 centimenters in diameter made from the same material?
i know that the equation should look something like this:
R=k L/D^2
but from there i get lost when plugging in the values
36ohms=k (20m)/(.6cm)^2
if i can figure out K i can plug in the other values and get my answer.
i figure i have to make m into cm so 20 becomes 2000cm/.36cm if i times by 100
to get rid of the decimal in denominator i get 3600oms=K* 200000/36
multiply both sides by 36 and i get 129600oms=200000K
divide by 200000
k=.648
pluggin in the values that i have from above i get the resistance would be 27ohms.
Click here to see answer by josmiceli(9819)

Question 46598: Find the x-intercept of the following equation
y = x^2 + x - 6
I get
0 = x^2 + x - 6
I should use the quadratic formula to get
x = ??? THis is where I am lost and I have an assignment due today and can't figure this one out.
If someone can help please.
Click here to see answer by Nate(3500)

Question 46666: The base of a 15-ft ladder is 5 feet away from a wall. How far above the floor is the top of the ladder. Give answer to the nearest thousandth.
Sentence problems are confusing can you help please.
Thanks
Click here to see answer by Nate(3500)

Question 46778: The length of a rectangle is 3 cm more than 4 times its width. If the area of the rectangle is 79 cm^2, find the dimensions of the rectangle to the nearest thousandth.
To start should it be - using x for the width and l for the length
l = s(4) + 3
Is there anyone who can help and thank you.
Click here to see answer by Nate(3500)

Question 46815: What is the main concept of how to figure out these problems, cause we did it all day in class, and i couldn't do it can you send an example of any problem please i'd really appreciate it.
Click here to see answer by tutorcecilia(2152)

Question 46817: Evaluate the variable expression 3xy-7x+35 for x=10 and y=4?
Click here to see answer by tutorcecilia(2152)

Question 46790: Write the expression in the form a + bi.

Click here to see answer by adamchapman(301)

Question 46820: 10x + 60 divided by (2y)
for x=2 and y=5
What is the answer?
Click here to see answer by consc198(59)

Question 46976: Perform the indicated operation and expression lowest terms.

Click here to see answer by gsmani_iyer(180)

Question 47103: (4y-2)(3y-7)
Click here to see answer by tutorcecilia(2152)

Question 47103: (4y-2)(3y-7)
Click here to see answer by squid53(1)

Question 47141: One number is 4 times another. If the sum of their reciprocals is 1/8, find the two numbers.
To start I get (I think)
x + 4(x) = 1/8 but not sure where to go from here.
Thanks for help.
Click here to see answer by adamchapman(301)

Question 47181: I believe I'm missing a step. my answer is x=12, but when I check my solution it does not come out right. here is the problem:6x+5+7x+3=12x+4
Click here to see answer by adamchapman(301)

Question 47403: Hi,
I would really appreciate some assistance with this problem:
A chemist mixes an 11% acid solution with a 4% acid solution. How many milliliters of each solution must he use to get 700 milliliters of a 6% solution?
Thanks,
Louis
Click here to see answer by Earlsdon(6294)

Question 47421: I am trying to solve and simplify the following
1 + 2/3
divided by
2 + 1/2
Can someone assist me with this please and thank you.
Click here to see answer by mszlmb(115)

Question 47545: The equation h = - 16t^2 + 112t gives the height of an arrow, shot upward from the ground with an initial velocity of 112 ft, where t is the time after the arrow leaves the ground. Find the time it takes for the arrow to reach a height of 180ft.
Click here to see answer by stanbon(57984)

Question 47614: The perimeter of a rectangle is 420 inches. The width is 4 inches less than the length. What is the length of the rectangle?
Click here to see answer by checkley71(8403)

Question 47654: I have to simplify the rational function of (x2 - z2)/(x + z)
I have come to 2-z and x+2 and now am sure I am not doing something correctly. Please help!
Click here to see answer by stanbon(57984)

Question 47653: I have to evaluate the binomial (2y-1)^2
I get 2y^2+1 but am not sure if it is right. Can you help please?
I am not sure if the sign for 1 is correct and not sure what evaluate the binomial means. Thank you in advance for any help.
Click here to see answer by stanbon(57984)

Question 47682: Please help solve
6(2 – x) = 4x
Click here to see answer by Nate(3500)

Question 47685: Please help solve 4(x + 2) – 3x = x – 6
I m thinking there is no solution.
Click here to see answer by Nate(3500)

Question 47685: Please help solve 4(x + 2) – 3x = x – 6
I m thinking there is no solution.
Click here to see answer by checkley71(8403)

Question 47684: Help Solve Please . –6(x + 3) – 10 = 3(–2x – 5) – 13
Click here to see answer by Nate(3500)

Question 47683: The length of a rectangular garden is 3 ft less than 2 times its width. If the perimeter of the garden is 54 ft, find the dimensions of the garden.
Click here to see answer by Nate(3500)

Question 47749: factor the algebraic expressions completely.
16x^2 + 40x + 25
Click here to see answer by Earlsdon(6294)

Question 47748: factor the algebraic expressions completely.
4x^2 + 34x + 42
Click here to see answer by checkley71(8403)

Question 47747: factor the algebraic expressions completely.
x^2 – 16x + 63
Click here to see answer by Earlsdon(6294)

Question 47746: Multiply: (3x + 4) (3x - 4)
Click here to see answer by tutorcecilia(2152)

Question 47744:
Evaluate P(-1/2) if P(x) = 2x4 + x3 + 12
Click here to see answer by pizza(14)

Question 47877: Is –4 a solution to the equation 7 – 4x = 23?
Click here to see answer by Nate(3500)

Question 47872: Solve. 9x – 0.14 = 8(x – 0.42)

Click here to see answer by smath(6)

Question 47871: Solve for x. 10(–x – 7) + 20 = –5(2x + 4)
Click here to see answer by smath(6)

Question 47745: Simplify: (-4 + x2 + 2x3) – (-6 – x + 3x3) – (-6y3 + y2)
Click here to see answer by 1980.vikas(7)

Question 48052: write x^4/5 as a radical expression
Click here to see answer by stanbon(57984)

Question 48051: solve for X 3-2x<9
Click here to see answer by nik_consult(24)

Question 47985: I really don't think this is a variable involving problem but i need help.
ok my question is= 5x2(number 2 is an exponent wich goes on top of x)-10x.
ok in simple form is 5x2-10x
Click here to see answer by stanbon(57984)

Question 48131: Solve the system 4x-7y=3 and x=2/3y + 4 and check your solution
Click here to see answer by cowess(34)

Question 48262: how is this problem solved? I do not understand.
6x+1x^2=27
Thanks!
Click here to see answer by checkley71(8403)

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