zaterdag 11 juli 2015

Kwadraatafsplitsen is echt handig

\( \eqalign{ & 6x^2 - 11x - 10 = 0 \cr & 6\left( {x^2 - {{11} \over 6}x} \right) - 10 = 0 \cr & 6\left( {\left( {x - {{11} \over {12}}} \right)^2 - {{121} \over {144}}} \right) - 10 = 0 \cr & 6\left( {x - {{11} \over {12}}} \right)^2 - {{121} \over {24}} - 10 = 0 \cr & 6\left( {x - {{11} \over {12}}} \right)^2 - {{361} \over {24}} = 0 \cr & 6\left( {x - {{11} \over {12}}} \right)^2 = {{361} \over {24}} \cr & \left( {x - {{11} \over {12}}} \right)^2 = {{361} \over {144}} \cr & x - {{11} \over {12}} = - \sqrt {{{361} \over {144}}} \vee x - {{11} \over {12}} = \sqrt {{{361} \over {144}}} \cr & x - {{11} \over {12}} = - {{19} \over {12}} \vee x - {{11} \over {12}} = {{19} \over {12}} \cr & x = - {2 \over 3} \vee x = 2{1 \over 2} \cr} \)