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$For what values of $x$ is it true that $x^2 - 5x - 4 \le 10$? Express your answer in interval notation.$

Guest Oct 26, 2014

+121

+5

Best Answer

CPhill, you are great.

robtre Oct 26, 2014

robtre · Answer 1 · 2014-10-26T11:42:01

CPhill, you are great.

Guest · Answer 2 · 2014-10-26T10:21:27

I need this answered ASAP please.

CPhill · Answer 3 · 2014-10-26T10:30:35

x^2 - 5x - 4 ≤ 10 subtract 10 from both sides

x^2 - 5x - 14 ≤ 0 set this = 0 and factor

(x - 7)(x +2) = 0 so x = 7 and x = -2

So we have three iintervals here to evaluate x ≤ -2, -2 ≤ x ≤ 7 and x ≥ 7

So using (x-7)(x+2) and testing x =-3 makes this > 0

And testing x = 0 makes (x-7)(x +2) < 0

And testing x = 8 makes it > 0

So our answer is

-2 ≤ x ≤ 7

Guest · Answer 4 · 2014-10-26T10:32:12

Thanks! by the way, the one on the top is not written by me.

Melody · Answer 5 · 2014-10-26T11:31:56

I think this is the notation that you want - maybe

[-2,7]

Melody · Answer 6 · 2014-10-27T10:58:21

Yes he is!!

CPhill · Answer 7 · 2014-10-27T11:07:45

Aw shucks, folks.....it was nothing....really......!!!