Question 176182
{{{y^2-4y+4=36}}}
{{{y^2-4y-32=0}}}
You can factor this quadratic equation.
{{{(y-8)(y+4)=0}}}
Two solutions
{{{y[1]-8=0}}}
{{{y[1]=8}}}
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{{{y[2]+4=0}}}
{{{y[2]=-4}}}

Not sure about approximate solutions in this case.