Questions on Algebra: Quadratic Equation answered by real tutors!

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Question 493725: Really need some help please.
Given the quadratic function f(x) = x2 – 18x + 81, find a value of x such that f(x) = 16.
Click here to see answer by nerdybill(6951)

Question 493725: Really need some help please.
Given the quadratic function f(x) = x2 – 18x + 81, find a value of x such that f(x) = 16.
Click here to see answer by MRperkins(300)

Question 493948: Hi. I'm trying to do my algebra 2 GT homework and I have no idea how to do it by hand. I know how to plug it into the calculator and get the graph and answer, but I don't remember how to do so by hand. The problem says to "Graph the function. If a > 0 find the minimum value. If a < 0 find the maximum value. The function is y= . THANK YOU!!
Click here to see answer by Theo(3458)

Question 493431: find all solutions of the equation...
27x^3-512=0
i know i have to get the cube or something like that
or the GCF?
Click here to see answer by bucky(2189)

Question 494123: how would you solve 15=3(7m+5)

Click here to see answer by rfer(12647)

Question 494134: 15=3(7m+5)
Click here to see answer by rfer(12647)

Question 494134: 15=3(7m+5)
Click here to see answer by MathLover1(6622)

Question 494653: solve by factoring 9t^2+3t=0
Click here to see answer by MathLover1(6622)

Question 494398: I need help fast. What would us students do without this site and without you all to help us? Thank you all so much.
Using operations of order(PEMDAS)using multiplication, how do I solve these problems? -1(-3)^2, -1*3^2.

Click here to see answer by ankor@dixie-net.com(15638)

Question 494884: How does finding the equation given the solution and factoring relate?
Even though I am able to solve the problem I am having issues putting it into words. Thanks
Click here to see answer by josmiceli(9661)

Question 494920: a rock falls from a tower that is 320 feet high. As it is falling, its height is given by the formula h=320-16t^2. How many seconds (in tenths) will it take to get to the ground.(h=0)?
My solution
0=-16t^2+320t
0=-4t(4t-80)
4t=0 or 4t-80=0
t=0 or t=20
0 doesn't answer the question so I get 20 seconds. The answer key on my study sheet says 4.5 seconds. I am not sure what I did wrong. Thanks!
Click here to see answer by Alan3354(30983)

Question 495248: find the value of k so that the equation 5x^2-8x+k=0 will have roots whose product is equal to 2/3?

Click here to see answer by stanbon(57246)

Question 495898: Can you please explain to me why (x+4)^2 is not equal to x^2+16?
Thank you for taking the time to help me with this.
Click here to see answer by richard1234(5390)

Question 495908: Can you please explain to me why (x+4)^2 is not equal to x^2+16?

Click here to see answer by rfer(12647)

Question 495911: and . Can you tell me why they are not equal? I get the part when you say that they are different. But why are they? I have the answer to , but where is the solution to ? I am so confused.

Click here to see answer by kingme18(98)

Question 496076: Can you please help me by showing me how to solve the following. It says solve the equation by completing the square. x^2 +8x=5 Thank you!
Click here to see answer by chessace(471)

Question 496078: Can you please help me by showing me how to solve the following. It says write the expression in the standard for a+bi. -6i(-2+9i) Thank you!
Click here to see answer by chessace(471)

Question 496280: Where does the quadratic fromula come from?
-b plus or minus the square root of b squared minus 4ac all divided by 2a
Click here to see answer by richard1234(5390)

Question 497028: The length of a rectangle is twice the width. The area is 288 yd^2 find the length and width? PLEASE HELP ASAP?? THANK YOU!!!
Click here to see answer by jorel1380(2518)

Question 497116: Help me Please.

1. 16a^2-12a^2+24a^2b^2/4a^2. Find the quotient of the problem.
2. 3(2)*(2)-5(2)= Find the value of each expression when x=2.

Click here to see answer by stanbon(57246)

Question 497434: Please help me
1. find the quotient and write the the answer
in scientific notation (10*10^6)/5x10^-3=
2. Add 46x^2-100x-120 to 26x^2-49x+70=
3. write this number in scientific notation 41,700= ___ *10^.
Thank you so much.
Click here to see answer by lwsshak3(6472)

Question 497684: give exact and approximate solutions to three decimal places. x^2+16x+64=4
what are the exact solutions?
x=
Thank You For Your Time
Click here to see answer by solver91311(16868)

Question 498174: During the first part of a trip, a canoiest travels 35 mls. at a certain speed. The canoiest travels 9 mls. on the second part of the trip. at a speed of 5 mls. slower. The total time for this trip is 2 hrs. What was the speed on each part of the trip?
Click here to see answer by mananth(12270)

Question 498166: solve the following equations.
1. 1/(x-2)^2 + 1/(x-2) -6 =0
2. 2/(x+1) - 5/(sqrt x+1) +3 =0
Click here to see answer by lwsshak3(6472)

Question 498634: When filling in the table of values for y = x^2, I noticed the values of y differ by a series of odd numbers: if x = 0, 1, 2, 3, 4... then y = 0, 1, 4, 9, 16... the y values differing by 1, 3, 5, 7... For y = (1/8)(x-4)^2 +5, the x values 4, 5, 6, 7... give y = 5, 5.125, 5.500, 6.125, 7... which works out to a difference of 1*(1/8), 3*(1/8), 5*(1/8), 7*(1/8)...
Why does this happen?
Click here to see answer by richard1234(5390)

Question 498825: I don't understand how to solve this problem. Thank you.
It says solve and check the quadratic equation below by taking the square root of both sides. Express irrational answers in rational form.
(x-10)^2=4
thank you so much
Click here to see answer by Theo(3458)

Question 498870: how can i find a teacher who will really teach me?
Click here to see answer by mananth(12270)

Question 498856: I do not understand how to solve this problem. It says solve and check the following equation.
3+(√3a+3)=9
thank you
Click here to see answer by Earlsdon(6287)

Question 498924: use the discriminant to determine the number of solutions and whether they are real or complex.
x^2 + 6x - 7 = 0
z^2 + z + 1 = 0
(3)^1/2 y^2 - 4y - 7(3)^1/2 = 0
I can not figure these three out. Please help! Thanks
Suzie
Click here to see answer by chessace(471)

Question 498978: factor completely and find the root of the expression
49x^2 -14x -3
Can you please help me with this?
Suzie
Click here to see answer by Alan3354(30983)

Question 498978: factor completely and find the root of the expression
49x^2 -14x -3
Can you please help me with this?
Suzie
Click here to see answer by htmentor(788)

Question 498664: 2x^2+19x=-24 i need work for solve each quadratic by factoring

2(x-3)^2=8 by using sqaure roots

Click here to see answer by ankor@dixie-net.com(15638)

Question 499027: b(b+9)=4(5+2b)
Click here to see answer by deborabr(181)

Question 499020: By increasing her usual speed by 25 kilometers per hour, a bus driver decreases the time on a 25-kilometer trip by 10 minutes. Find the usual speed.

The Vilas County News earns a profit of $20 per year for each of its 3,000 subscribers. Management projects that the profit per subscriber would increase by 1¢ for each additional subscriber over the current 3,000. How many total subscribers are needed to bring a total profit of $113,100?

Perform the operations and simplify. 1/x times x^2-15x all over x-14
Click here to see answer by ankor@dixie-net.com(15638)

Question 498976: 2x^3=-2
Click here to see answer by rfer(12647)

Question 499103: how would you set up an equation to represent "a rowboat is 11 times as long as it is wide"? with an explanation please. I teach and this is a test question and my fellow teachers and myself do not understand the answer that we are given
Click here to see answer by jim_thompson5910(28504)

Question 499114: Ignoring wind resistance, the distance "d" in feet that a parachute falls in "t" seconds can be estimated using this formula d= 16t^2. If a parachutist jumps from an airplane and falls for 1100 feet before opening the parachute, how many seconds pass before the parachute is opened?
Click here to see answer by ankor@dixie-net.com(15638)

Question 499226: quadratic equations
i am not looking for the working out of this question
3 - 2x - 8x^2
how do you get it to resemble the formula
ax^2 + bx + c
do you bring the 8x^2 to the left side and make it positive as well as te 2x?
Click here to see answer by nerdybill(6951)

Question 499286: What the importance of quadratic equations to a basketball player, diver, or even a sniper. Give an example of a real-world situation where you would apply quadratic equations.

Click here to see answer by chessace(471)

Question 499267: 9^(7-2)=1/243
please help,
at first i changed the left and right numbers into values that were similar
(3^2)^(7-2x) = 1/3^5
were would i go from here and explain the laws of indices needed to solve this problem
Click here to see answer by Alan3354(30983)

Question 499392: In questions 6-10, use the discriminant to determine the number of solutions of the quadratic equation, and whether the solutions are real or complex. Note: It is not necessary to find the roots; just determine the number and types of solutions
4/3x^2 -2x + 3/4 = 0
This is the one that has me going in circles please help.
Suzie
Click here to see answer by jim_thompson5910(28504)

Question 499424: solve the system of equation using substitution to eliminate one variable.
y=2x
3x+y=20

I don't know how to work this out.
Click here to see answer by oberobic(2304)

Question 499460: 36x^2-12x+1=0
Click here to see answer by jim_thompson5910(28504)

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