Question 950449

{{{2x^2 - 13x +21 = 0}}}
{{{2x^2-6x - 7x +21 = 0}}}
{{{(2x^2-6x) - (7x-21) = 0}}}
{{{2x(x-3) -7 (x-3) = 0}}}
 {{{(x-3) (2x-7) = 0}}}

solutions:
{{{x = 3}}} 
{{{ x = 7/2}}}=>{{{x = 3.5}}}



{{{2x^2+ 9x-56 =0}}}
{{{2x^2+ 16x-7x-56 =0}}}
{{{(2x^2+ 16x)-(7x+56) =0}}}
{{{2x(x+ 8)-7(x+8) =0}}}
{{{(2x-7) (x+8)=0}}}

solutions:
{{{x = -8}}}
{{{x = 7/2}}}=>{{{x = 3.5}}}


both functions have one root in common and that is {{{x = 3.5}}}

means, if you plug {{{x = 3.5}}} in both equations will be equal to zero, so graphs intersect in a point ({{{3.5}}},{{{0}}}) 


{{{ graph( 600, 600, -10, 10, -60, 60, 2x^2 - 13x +21, 2x^2+ 9x-56) }}}