f(x) x^2+x-6 Solve F(x) > 0
X^2-3x+2x-6
X(X-3)+2(x-3)
(x+2)(X-3)
X E (-oo,-3)U(2,oo)
So my question is why is it -3 and 2 instead of -2 and 3. when it is -2 or 3 that would make (x+2)(X-3)=0
2007-08-18 09:54:04 · 3 answers · asked by roguetrader12002 4 in Science & Mathematics ➔ Mathematics
You made a small mistake factoring...
x^2 + x - 6
= x^2 + 3x - 2x - 6 (notice the signs)
= x(x + 3) - 2(x + 3)
= (x + 3)(x - 2)
2007-08-18 10:00:35 · answer #1 · answered by whitesox09 7 · 0⤊ 0⤋
x^2 + x - 6 = x^2 -2x + 3x - 6 = x(x - 2) + 3(x - 2) =
= (x + 3)(x - 2)
x<-3 --> x+3 < -3 + 3 = 0 and x-2 < -3 -2 = -5 < 0 ->
(x + 3)(x - 2) > 0
Likewise, if -3 <= x <= 2 (x + 3)(x - 2) <=0
and if 2
2007-08-18 17:07:54 · answer #2 · answered by Amit Y 5 · 0⤊ 0⤋
Your concept is right, but you missed the sign.
f(x)
= x^2+x-6
= x^2+3x-2x-6
= x(x+3)-2(x+3)
= (x-2)(x+3) > 0 =>x â (-oo,-3)U(2,oo)
2007-08-18 17:02:11 · answer #3 · answered by sahsjing 7 · 0⤊ 0⤋