Tuesday, August 13, 2013

Express the solution to the following inequality using interval notation. x^2 + 7x - 18 ≥ 0

x^2+7x-18=
(x+9)(x-2) 

and since a=1 (a>0) we know that it opens upwards. 
this implies that it is negative on (-9,2)
therefore our solution is... 
(-oo,-9]U[2,oo)

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