Question 48549
1.)Graphing (at most times, not very accurate)
{{{graph(600,600,-10,10,-10,10,12x^2-10x-42,0)}}}
2.)Factoring
{{{12x^2 - 10x - 42 = 0}}}
{{{6x^2 - 5x - 21 = 0}}}
{{{6x^2 + 9x - 14x - 21 = 0}}}
{{{(6x^2 + 9x) + (-14x - 21) = 0}}}
{{{3x(2x + 3) - 7(2x + 3) = 0}}}
{{{(3x - 7)(2x + 3) = 0}}}
3x - 7 = 0
3x = 7
x = 7/3 or 2 1/3
and
2x + 3 = 0
2x = -3
x = -3/2 or -1 1/2
3.)Completing the Square
{{{12x^2 - 10x - 42 = 0}}}
{{{6x^2 - 5x - 21 = 0}}}
{{{x^2 - 5x/6 = 7/2}}}
{{{(x - 5/12)^2 = 25/144 + 504/144 = 529/144}}}
{{{x - 5/12}}} = +-{{{23/12}}}
{{{x = 5/12 +- 23/12}}}
{{{x = (5 +- 23)/12}}}
4.)Quadratic Formula
{{{x = (-b +- sqrt( b^2 - 4*a*c ))/(2*a) }}}
{{{x = (5 +- sqrt( 25 + 504 ))/(12) }}}
{{{x = (5 +- 23)/12}}}