Find the value of x when 2x^2 - x - 6 = 0
2x2 - x - 6 = 0
This must first be factorised - I use the 'box method' when the reciprocal of x2 is >1. This is difficult to explain via writing but it involves a little trial and error.
2x + 3 --> (+3x)
x - 2 --> (-4x)
Therefore 2x2 - x - 6 = 0 can be factorised to give (2x+3)(x-2) = 0 - At this stage, you should multiply it out to check that you get the original equation.
if 2x+3 = 0 --> 2x= -3 giving x = -3/2
if x-2 = 0 --> x = 2
Final check can be done by substituting each value of x into the original equation and ensuring the answer is 0.
GS
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