Thursday

July 24, 2014

July 24, 2014

Posted by **Heather** on Tuesday, November 20, 2012 at 10:00pm.

70x-51<70/x

I get this--but I do not know how to write the final answer in a solution set

70x-51<70/x

70x^2/x - 51x /x - 70/x < 0

70x^2 - 51x - 70/x <0

(10x + 7) (7x - 10)/x <0

x=0

(10x + 7)= 0

(7x - 10)=0

Can you please help me to write the answer in a solution set???

- college algebra--please help -
**Steve**, Tuesday, November 20, 2012 at 11:03pmwhen you get to this point:

70x^2/x - 51x /x - 70/x < 0

multiply by x to get

70x^2 - 51x - 70 < 0 and note that x≠0

since 1/x is not defined for x=0

now you have

(10x+7)(7x-10) < 0

At this point you should have some idea what you are looking for. You know it is a parabola which opens upward, and crosses the x-axis at -7/10 and 10/7.

So, the interval between the roots satisfies the original inequality:

-7/10 < x < 10/7

Algebraically, since

(10x+7)(7x-10) < 0, either

(10x+7) < 0 and (7x-10) > 0

or

(10x+7) > 0 and (7x-10) < 0

solve those and you will find a solution set which agrees to the interval above.

- college algebra--please help -
**Steve**, Tuesday, November 20, 2012 at 11:05pmoops. because x cannot be 0, the final solution is

(-7/10,0) U (0,10/7)

**Related Questions**

calculus - f(x)=(2x-1)^2(x^2-9) find f'(x)=0 So first derivative: f'(x)=16x^3-6x...

Pre-Calc - I am having a great deal of difficulty with this problem. An open box...

math - need to calculate total purchase price I can afford for a home. monthly ...

algebra - Solve: C(x)=70x-1000

algebra - 70x-1=10x-70

Math - (x+20)(x-9)(x+10)>0 Please help? I'm stuck...need to find the solution...

college algebra - use the given zero to find the remaining zeros of the function...

College Algebra - 49x^4 - 70x^3 + 21x^2. Facotor out, relative to the intergers...

Precalculus - Write the given expression as a single logarithm. log(70x)+log(10y...

math - Find all real and Imaginary solutions 7x^(3)+70x^(2)-x-10=0