Question 827345
 

first find values for which {{{ (x-7)(x+5)=0}}}

if {{{x-7=0}}} => {{{x=7}}}

if  {{{x+5=0}}} => {{{x=-5}}}

for values less than {{{7}}} (like {{{6}}}, {{{5}}},...to {{{-infinity}}}), the quantity {{{(x-7)(x+5)}}} is negative

for values less than {{{-5}}} (like {{{-6}}}, {{{-7}}},...to {{{-infinity}}}),  the quantity {{{(x-7)(x+5)}}} is negative


{{{ graph( 600, 600, -10, 10, -10, 10,(x-7)(x+5))}}}