Question 298458
z^2 + 12z + 15 = 0
{{{z = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
z=(-12+-sqrt[12^2-4*1*15])/2
z=(-12+-sqrt144-60])/2
z=(-12+-sqrt84)/2
z=(-12+-9.165)/2
z=(-12+9.165)/2
z=-2.835/2
z=-1.4175 ans.
z=(-12-9.165)/2
z=(-21.165)/2
z=-10.5825 ans.