Question 105096
{{{(x-5)(x+2)=18}}}

{{{(x-5)(x+2)=x(x+2)-5(x+2)}}}
{{{(x-5)(x+2)=(x^2+2x)-(5x+10)}}}
{{{(x-5)(x+2)=x^2+(2x-5x)+10}}}
{{{(x-5)(x+2)=x^2-3x+10}}}

So,

{{{x^2-3x+10=18}}}
{{{x^2-3x+10-18=18-18}}}
{{{x^2-3x-8=0}}}

Using the quadratic formula,

{{{x=(3+-sqrt(3^2-4*1*(-8)))/(2*1)}}}
{{{x=(3+-sqrt(9+32))/(2)}}}
{{{x=(3+sqrt(41))/(2)}}} or {{{x=(3-sqrt(41))/(2)}}}

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