Question 1068858
*[illustration der5.JPG].
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{{{y=x+3}}}
Substituting,
{{{x(x+3)=12}}}
{{{x^2+3x=12}}}
{{{x^2+3x+(3/2)^2=12+(3/2)^2}}}
{{{(x+3/2)^2=48/4+9/4}}}
{{{(x+3/2)^2=57/4}}}
{{{x+3/2=0 +- sqrt(57)/2}}}
{{{x=-3/2+- sqrt(57)/2}}}
{{{x=(-3 +- sqrt(57))/2}}}