Quadratic formula problem.

[Benjo]

i got a problem in maths so please help me

2x + 3 4x+7

-------- + ------- = 7

2x-3 2x-4

another one:

x(x-5) -3 = (2x-1)² -4

please show me the whole way

 

[Milksteak]

Someone should have payed attention in class..

 

[.frenchy]

for the second one are you solving for x, or am i stupid lol?

 

[beowulf]

what else would you solve for...

 

[dubaiski]

as far as i can see you dont need he quadratic formula for either
the second one is 0=(x+1)(x-1) so X= 1 or -1
the first is long winded and i cant be bothered.
i did it quickly so check it over before you hand it in

 

[comeatmebro]

for the 2nd i believe you get x=0 and x=-1/3. so x=-1/3. don't wanna type out the work really.

 

[Benjo]

i'll check it

+k for sure anyway

 

[Benjo]

+k also for you sir

 

[dubaiski]

scrap that, the guy above me was right, i forgo to carry an x. And BTW it snot hard, i wont write it all out because you wont learn from it. Just square out the brackets, move it all to one side and factorise.
pm me if you have any questions

 

[chacho]

heres how i got -1/3 for x, its pretty easy

x(x-5)-3=(2x-1)^2-4

2x-5x-3=(2x-1)(2x-1)-4

-3x-3=4x-2x-2x-2

-3x-3=0-2

-3x=1

-x=1/3

x=-1/3

 

[Benjo]

thank you

+k

 

[SOLID7]

Quadratic formulas often have two answers so be careful -_-. Try solving this one for fun:
Square root of -6. It's easy, trust me.

 

[chapz]

2x + 3 4x+7

-------- + ------- = 7

2x-3 2x-4

ok well i think you can just use cross multiplication...

2x+3/2x-3 = 4x+7+14x-28/2x-4

(2x+3)(2x-4) = (2x-3)(18x-21) ->(i cross multiplied, after using common denominator of 2x-4 on right hand side)

(4x^2 -2x-12) = (36x^2 -42x-54x+63)

(4x^2 -2x-12) = (36x^2 -96x+63)

4x^2 -2x-12-36x^2+96x-63=0

-32x^2 +94x-75=0 -> solve using quadratic formula

might not work, but it should.

 

[lahnabonny]

x times x = x squared, not 2x

 

[J.DUKE]

yes. i knew something looked funny

 

[reazzysteezy]

no you can't cross multiply until you solve the left side for one fraction. you can cross multiply when you have a fraction = a fraction

 

[Bepo]

I never knew ns was so mathematically challenged

 

[BootySpunk.]

I will give you hints.

1. Find a common denominator and than set the equation equal to 0 by subtracting 7.

2. Don't be an idiot and do some simple ass foiling and algebra and set the equation equal to zero by doing algebraic stuff.

 

[Steezy_IN_KC]

This might help you a little bit now.. and probably down the road a bit...
http://www.wolframalpha.com/input/?i=x%28x-5%29+-3+%3D+%282x-1%29²+-4

works for me.

 

[no_steeze]

i literally learned this in 7th grade

 

[Benjo]

thanks to all of you guys! kinda helped me out...

btw its pretty funny to discuss about maths. lol

 

[samsquamch]

2nd problem is x=0, x=-1/3 get those answers by completing the square and gettin one side equal to 0 (so that you can derive x using the quadratic formula). the -4ac will cancel because there is no c value in your equation you'll plug in, so dont worry about your equation looking funny

the first one i dont really feel like doin but get a common denominator and bring the 7 to the other side if you want to use the quadratic formula to solve for x because one side has to be equal to zero for the quadratic formula to work

 

[karmagod]

Seriously, how fucking old or stupid are you? You're dealing with super basic algebra problems there. You should seriously learn this shit rather than ask NS to do your homework for you.

 

[killa_cam]

1) Multiply both sides by (2x-3)*(2x-4). x=1.625=13/8, x=4.5=9/2

2) Just expand. x=0, x=-0.33=-1/3

 

[mathmansam]

anything is a fraction if you put it over 1....

 

[chapz]

i did...

did you not look over my work?