Help please

K

kaebun

Junior Member
Joined
Sep 11, 2005
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135
when you have an equalitie and you take the square root do you flip the sign?
 
I don't think you can take the square root of an inequality. I could be wrong, of course....

Eliz.
 
the problem is x^2=9<6x except the sign is less than or equal to[/code]
 
opps i meant x^2+9<or=6x
but i think i got it now is it x<or+3 ?
 
I will guess that you mean the following:

. . . . .x<sup>2</sup> - 9 < 6x

If so, then get the quadratic all together on one side:

. . . . .x<sup>2</sup> - 6x - 9 < 0

Find the zeroes of the associated equality, x<sup>2</sup> - 6x - 9 = 0. The quadratic will be either above the axis (positive) or below the axis (negative) everywhere it isn't zero. What intervals then do you have? And on which of these intervals is the quadratic above the axis?

Eliz.

P.S. To do "or equal to" on the inequalities, use the "underline" button to underline the inequality sign.
 
Okay, but the process is exactly the same, regardless: Find the zeroes, and then find where the parabola is above or below the axis between those zeroes.

Eliz.
 
i think thats what i did :) im feeling stupid right now im usally very good with math
 
Take a break; watch something on TV; decompress for a bit. Sometimes math goes easier after you take a little breather. :wink:

Eliz.
 
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