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Solving Quadratics Recap

METHOD 3: The Quadranator

*After a failed 10 second factor attempt,
whack it with this and it will work every time. 
The problem is: If you forget the formula, you're dead meat.

ax^2 + bx + c = 0 ... x = -b +/- sqrt( b^2 - 4ac ) / 2a

Example:

Solve  3x^2 - 10x + 1 = 0

 

x = - ( -10 ) +/- sqrt( ( -10 )^2 - 4 ( 3 ) ( 1 ) ) / ( 2 (3 ) ) = 10 +/- sqrt( 100 - 12 ) / 6 = 10 +/- sqrt( 88 ) / 6

exact: { 10 - sqrt( 88 ) / 6 , 10 + sqrt( 88 ) / 6 }

decimal approximation: { .103 , 3.230 }

TRY IT:

Solve  2x^2 + 11x + 1 = 0