Question 161257
The discriminant for a quadratic equation is given by 
{{{b^2-4ac}}} when the equation is in the form
{{{ax^2+bx+c=0}}}
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{{{7 + 5z^2 = 2z}}}
Rearrange the equation,
{{{5z^2-2z+7=0}}}
In your case, 
{{{a=5}}}
{{{b=-2}}}
{{{c=7}}}
The discriminant is then, 
{{{b^2-4ac=(-2)^2-4(5)(7)}}}
{{{b^2-4ac=4-144}}}
{{{b^2-4ac=-148}}}
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The discriminant gives you information regarding the roots depending on its value. 
If {{{b^2-4ac>0}}}, you have two distinct real roots.
If {{{b^2-4ac=0}}}, you have two coincident real roots.
If {{{b^2-4ac<0}}}, you have two complex roots (complex conjugates).
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Since {{{b^2-4ac=-148}}}, you will have two complex conjugate roots.