I cannot figure out how to get x from this problem. Thanks a lot!
I am having trouble figuring out: 9x^2 + 18x + 5 =0
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f(x) =9X2 +18X + 5
First check factorability of the quadratic, find out whether there exist 2 integers , a, b, such that
their Sum equals 18, and their product is 9*5 =45
To do that :
Write 45 as product of its factors: 45 = 3 * 15 = 9 * 5
Observe that 3+ 15 =18
f(X) = 9X2 +15X + 3X +5 /Break up 18X = 15X +3X
3X(3X + 5 ) +(3x +5) / factor the quadratic by grouping
( 3X + 5 )( 3X + 1) =0
3X + 5 = 0 X = -5/3
3X + 1 = 0 X = -1/3
In the event if, in quadratic aX2 + bX +c
there is no 2 integers , m;n, does not exist such that m.n= ac and m+n = b
Then to solve the quadratic you can either use factoring by completing square or
using quadratic formula.
9x2 + 18x + 5 =0
For the FOIL...
FIRST must be (3x)(3x) or (9x)(x).
OUTER and INNER must add-up to 18x.
LAST must be (5)(1) or (1)(5).
One or both of the parenthetical equations must equal zero.