I dentify the solution for

2x^2+1

Question

I dentify the solution  for

2x^2+1< 9x-3

anonymous · Answer

$$2x^2-9x+4<0$$ is a start

saifoo.khan · Answer

Then?

saifoo.khan · Answer

OIC,

anonymous · Answer

$$(x-4)(2x-1)<0$$

saifoo.khan · Answer

So, 

x < 4

x <1

saifoo.khan · Answer

?

anonymous · Answer

so zeros are at 4 and 1/2 and since this is a parabola facing up it is negative between the zeros.

saifoo.khan · Answer

Lol, idk. Satellite plz correct me

anonymous · Answer

yes of course you are wrong

anonymous · Answer

answer is 
$$(\frac{1}{2},4)$$

anonymous · Answer

or 
$$\frac{1}{2}<x<4$$ if you prefer

saifoo.khan · Answer

So, 

x < 4

x <1/2

right?

anonymous · Answer

nope

saifoo.khan · Answer

Then? :S

anonymous · Answer

you have a produce. product is negative when one factor is positive and the other is negative.  that is if x is greater than 1/2 and less than 4

anonymous · Answer

what method did u use to factor?

anonymous · Answer

@chelsea eyeball method

saifoo.khan · Answer

(x−4)(2x−1)<0

how will you solve this?

anonymous · Answer

otherwise you can find the zeros using quadratic formula

anonymous · Answer

@saifoo i just did.  
$$y=(x-4)(2x-1)$$ is a parabola facing up. it has zeros at1/2 and 4.  so it is negative between them and positive outside.  think of the picture (graph)

saifoo.khan · Answer

O, thnks!

i was confused b/w 0 & y.

anonymous · Answer

Satellite has figured the correct solution to the equality, not the inequality. The solution is a range of values between but not including 1/2 and 4. Graph the function and see that the part that is below the x-axis  represents the solution where f(x) < 0. The answer would be expressed like a <x <b or (a,b). Do you know what a and b are for this problem?

anonymous · Answer

@statman solution is written both ways abut 5 lines or so above