Questions on Algebra: Quadratic Equation answered by real tutors!

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Question 901776: Good day
I have something puzzling me for quite a while now
Let't take an example
In the quadratic equation
1. 72c2 + 24c - 16
The answer is (12c - 4) (6c + 4)
Firstly.. Why 12 and 6? why not something like 9 and 8
Tried the formula with this example numbered as "1."
Secondly.. How do I know from the equation "72c2 + 24c - 16" which bracket is going to get the "+" and which bracket is going to get the "-"
They explained it in school but I just can't remember the principles.
Kind Regards.
Stefan.
Click here to see answer by ewatrrr(24785)

Question 901893: 9r2-5r-10=0
iam trying to help my son solve this equation
(9r-2)(1r-5)
Click here to see answer by richwmiller(17219)

Question 901966: a framed picture has lenght 35 cm and width 25 cm. the picture itself has area 375 cm. how far is it from the edge of the picture of the frame if its distance is uniform around the picture
Click here to see answer by nerdybill(7384)

Question 902111: Please help me!!!
The area of 10 cm by 25 cm rectangle is doubled by what equal amount must each dimension be increased?
assignment for tomorrow. help me asap!!
Click here to see answer by ewatrrr(24785)

Question 902101: What is the answer to 46 - y = 256 ?
Click here to see answer by lenny460(1073)

Question 902187: Algebraically find the the vertex
y=6+x-x^2
I know how to find vertex, i am just confused if c=6 b=x a=-x^2 or do i have to change the equation to make it positive like x^2-x-6 instead. Not sure if that makes a difference.
Thanks in advance

Click here to see answer by ewatrrr(24785)

Question 902329: if marcie swims 5 laps on day 1, 6 laps on day 2, 8 on day 3, and 11 on day 4, how many will she swim on day 5 and how did you get the answer?
Click here to see answer by ankor@dixie-net.com(22740)

Question 902554: X-(X*.10)=Z
find the value of x if z is the only given number
Click here to see answer by josgarithmetic(39617)

Question 902578: Hello,
I need help completing the square, I would appreciate your help
x^2+dx+49

and
x^2+dx+9/4
Thank You!
Click here to see answer by Fombitz(32388)

Question 902465: How do you graph 2(x+3)^2 -4
Click here to see answer by Fombitz(32388)

Question 902600: (1/x-2)^2=1/9
Click here to see answer by ewatrrr(24785)

Question 902640: When the sum of 424 and three times a positive number is subtracted from the square of the number, the result is 126. Find the number.
Click here to see answer by ewatrrr(24785)

Question 902637: the length of a closed box is 3 times its height, and it is 4 cm wide. if the total surface area is 88 cm^2, find the dimensions of the box.
Click here to see answer by ewatrrr(24785)

Question 902628: the length of a lawn is 10 m more than the width, and the area is 600 m^2. Write the equation and solve it to find the dimensions of the lawn.

can someone please explain how you get the answer and what equation you are going to use i.e how are you going to get the equation with this information provided :):)
Click here to see answer by Stitch(470)

Question 902709: what do you do first in the equation 8+(9t+4)
Click here to see answer by Fombitz(32388)

Question 902709: what do you do first in the equation 8+(9t+4)
Click here to see answer by richwmiller(17219)

Question 902757: What is the answer to 5(18m+2)
Click here to see answer by ewatrrr(24785)

Question 902920: A group of 19 students want to see the show at the planetarium. Tickets cost $11 for each student who is a member of the planetariums frequent visitor program & $13 for each student who is not a member. The total cost of the students tickets is $209.
1. Write an equation to determine the value of x. Explain what each part of your equation represents.
Click here to see answer by josgarithmetic(39617)

Question 902950: find the quadratic function w/integral
coefficients having the given zeroes.
1. 4and 8

Click here to see answer by Fombitz(32388)

Question 903016: Which statement is true?
#1 The equation �3|2x + 1.2| = �1 has no solution.
#2 The equation 3.5|6x � 2| = 3.5 has one solution.
#3 The equation 5|�3.1x + 6.9| = �3.5 has two solutions.
#4 The equation �0.3|3 + 8x| = 0.9 has no solution.
Click here to see answer by tmwilliamlin168(27)

Question 902978: convert into quadratic form : -7x20-10x10+6
Click here to see answer by ewatrrr(24785)

Question 903097: The oriental rug shown is 5 feet longer than it is wide. If the diagonal of the rug is 12 feet find its dimensions to the nearest tenth of a foot.
Click here to see answer by ewatrrr(24785)

Question 903111: Solve the equation by introducing a substitution that transforms this equation into quadratic form.
x^4-35x^2+304=0
I'm not even sure how to begin this, but my paper has a spot for four answers if that helps?
Click here to see answer by ewatrrr(24785)

Question 903125: Solve the equation by introducing a substitution that transforms this equation to quadratic form.
z^2/5-12z^1/5+36=0
Click here to see answer by Fombitz(32388)

Question 152: two consecutive integers are added the square of their sum is 361, what are the integers?
Click here to see answer by abhishek425(1)

Question 903410: mathematical investigation for the quadratic inequalities ax2+bx+c>0,when b-4ac<0

Click here to see answer by rfer(16322)

Question 903719: Find the constant term that should be added to make the following expression a perfect-square trinomial. X^2+2x
Click here to see answer by ewatrrr(24785)

Question 903718: Find the constant term that should be added to make the following expression a perfect-square trinomial. X^2-8x
Click here to see answer by ewatrrr(24785)

Question 903729: Solve. (x � 3)^2 = 6 Solve a quadratic equation by completing the square
Click here to see answer by josgarithmetic(39617)

Question 903826: Solving Quadratic Equations Using Square Root/Factoring
The aspect ratio of a TV screen is the ratio of the screen�s width to its height. For HDTVs, the aspect ratio is 16:9. What is the width and height of a 42 inch screen TV? (42 inches refers to the length of the screen�s diagonal.) HINT: Use the Pythagorean Theorem. Round your answers to the nearest hundredth.
Click here to see answer by jim_thompson5910(35256)

Question 903923: Find the quadratic equation of the roots:
5+2i and 5-2i
Click here to see answer by mananth(16946)

Question 904079: At a certain vineyard it is found that each grape vine produces about 10 pounds of grapes in a season when about 600 vines are planted per acre. For each additional vine that is planted, the production of each vine decreases by about 1 percent. So the number of pounds of grapes produced per acre is modeled by
A(n) = (600 + n)(10 − 0.01n)
where n is the number of additional vines planted. Find the number of vines that should be planted to maximize grape production.
Click here to see answer by josmiceli(19441)

Question 904089: 5x^2-10x^2=-7+x+x^2 help with the solution
Click here to see answer by josgarithmetic(39617)

Question 904089: 5x^2-10x^2=-7+x+x^2 help with the solution
Click here to see answer by MathTherapy(10551)

Question 904332: use completing the square to solve 2x^2-4x-5=0 I am so rusty but i am sure i will remember once it starts to look familiar again
Click here to see answer by richwmiller(17219)

Question 904500: how to make this equation into a quadratic and how to solve it
x-5=14/x
(X minus 5 = 14 over X)
thanks for you time
Click here to see answer by ewatrrr(24785)

Question 904538: expand y=(x-2)^2-25 and write it in the form y=ax^2+bx+c
give the co-ordinates of the intercepts of the y-axis
give the co-ordinates of the y-intercept
please help
Click here to see answer by josgarithmetic(39617)

Question 904547: I jave restarted my math... My problem is = 3x+2 = 6x+4
Click here to see answer by Theo(13342)

Question 904911: Please help me with this!
12x^2-5x-7, using completing the square.
Thank you!
Click here to see answer by richwmiller(17219)

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