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Mathematics 6 Online
OpenStudy (anonymous):

im stuck, help me :( (one question done, one more left)

OpenStudy (anonymous):

"Solve the equation 4xˆ2 -4x + 7x - 7 = 2(x-1) by whichever method seems easiest. Explain why you decided to use the method you did."

OpenStudy (anonymous):

I'm stuck on which method I should find... none come to mind. What I did so far is simplify the equation like this: 4xˆ2 - 4x +7x - 7 = 2(x-1) 4xˆ2 + 3x - 7 = 2x - 2 4xˆ2 + x - 5 = 0

OpenStudy (anonymous):

After that, I don't know what to do... please help

OpenStudy (anonymous):

(don't know if I'm in the correct path either)

OpenStudy (australopithecus):

looks ok to me

OpenStudy (anonymous):

hey you again! : )

OpenStudy (anonymous):

is that all though...? no further simplification?

OpenStudy (australopithecus):

you could factor it or use completing the square method

OpenStudy (anonymous):

how do i do any of those? :s

OpenStudy (australopithecus):

you know how to complete the square factoring is just about using logic

OpenStudy (australopithecus):

Factoring Looking at the standard equation ax^2 + bx + c 4xˆ2 + x - 5 we know a = 4 b = 1 c = -5 so first we write (x + )(x + ) now we know that a = 4 so we have to account for that (just a guess) (4x + )(x + ) what time what gives c = -5 but adds or subtracts together to give b = 1

OpenStudy (australopithecus):

can you solve the rest?

OpenStudy (australopithecus):

I have a rule against teaching factoring I hate doing it, there are over 9000 questions related to factoring on this site

OpenStudy (anonymous):

"what time what gives c = -5 but adds or subtracts together to give b = 1" nothing... the factors of -5 are -5, -1, 1, 5

OpenStudy (anonymous):

if i multiply with any of those, i wouldn't end up getting 1 with their addition or subtraction

OpenStudy (australopithecus):

well consider that you have a 4x in the brackets

OpenStudy (australopithecus):

and think about how things multiply out (Lx + b)(x+c) = Lx^(2) + Lx(c) + b(x) + (c)b, that Lx is going to mess with your addition, let hero cover this though he is better at this precalc stuff

hero (hero):

"Solve the problem, then explain why you did what you did". Don't ya just love those kinds of questions?

OpenStudy (anonymous):

(4x+5) (x-1) !!!!

OpenStudy (anonymous):

Hero, definitively :p

hero (hero):

Okay, so now that you've figured out the steps, what will you say to explain why you chose the method you used?

OpenStudy (anonymous):

(4x+5) (x-1) 4x + 5 = 0 4x = -5 x = -1.25 and, x-1 = 0 x = 1

OpenStudy (anonymous):

well, I put, "I decided to use the method I did because I immediately recognized that I could simplify the equation and then factor it out, finding two answers."

hero (hero):

Okay, I guess that's good enough :P

OpenStudy (anonymous):

Awesome!! :D I got another one, now that you're here, but this one is tricky..... at least for me. "Find a radical equation of the form (square root)ax+b = x + c so that one solution is extraneous. Show the steps in solving the equation. a) Is there a value for h that makes it possible for the equation (Square root)x+h (end square root) + 5 = o to have any real number solutions? Explain. b) Explain the relationship between the solutions to the equation (square root)x-3(end square root)-2 = 0 and the graph of the function (square root)x-3(end square root)-2 = 0."

OpenStudy (australopithecus):

In the first part it is just asking I'm pretty sure for you to find an equation where one of the solutions is real and the other is imaginary

OpenStudy (australopithecus):

remember!!! you cannot take the square root of a negative

OpenStudy (anonymous):

i know we have covered that (i remember imaginary numbers), but i complete forgot this :\

OpenStudy (australopithecus):

well can you at least make an attempt?

OpenStudy (anonymous):

okay lets see so first i would have to substitute the variables with numbers, and include a negative number in the square root to make it an imaginary?

OpenStudy (anonymous):

i meant, to have an imaginary solution

hero (hero):

Try \(\large\sqrt{2x + 1} = x - 1\) and see what happens.

OpenStudy (anonymous):

thank you! I'm so sorry I feel alseep yesterday....... :\

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