Question 890743
{{{x=(7+- sqrt(49-4*c))/2}}}, according to general formula, if the quadratic polynomial equals 0.


{{{(7+sqrt(49-4c))/2-(7-sqrt(49-4c))/2=1}}}, initially expecting c>0 and the minus root is less than the plus root.


{{{(7+sqrt(49-4c))-(7-sqrt(49-4c))=2}}}
{{{7+sqrt(49-4c)-7+sqrt(49-4c)=2}}}
{{{2*sqrt(49-4c)=2}}}
{{{sqrt(49-4c)=1}}}
{{{49-4c=1}}}, after squaring both sides
{{{49=1+4c}}}
{{{4c=49-1}}}
{{{4c=48}}}
{{{highlight(c=12)}}}