Solve this equation using the splitting the middle term method. I've got the answers using discriminant method but a problem related to the +ve -ve sign arises.
9 y^2 + 72y -144=0

Asked by Chandan | 8th Dec, 2014, 11:33: PM

Expert Answer:

9 y squared space plus space 72 y space minus 144 equals 0 rightwards double arrow y squared space plus space 8 y space minus 16 equals 0 rightwards double arrow y equals fraction numerator minus 8 plus-or-minus square root of left parenthesis minus 8 right parenthesis squared minus 4 left parenthesis 1 right parenthesis left parenthesis minus 16 right parenthesis end root over denominator 2 cross times 1 end fraction space space space space space space equals fraction numerator minus 8 plus-or-minus square root of 128 over denominator 2 end fraction space space space space space space equals fraction numerator minus 8 plus-or-minus 8 square root of 2 over denominator 2 end fraction space space space space y space equals space minus 4 plus-or-minus 4 square root of 2 T h e space s u m space c a n n o t space b e space s o l v e d space u sin g space m i d d l e space t e r m space s p l i t t i n g space o r space i t space y e i l d s space a n space i r r a t i o n a l space v a l u e.

Answered by Prasenjit Paul | 9th Dec, 2014, 10:32: AM

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