Question 247808
x^2+4x+13=0
{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}} 
X=(-4+-SQRT[4^2-4*1*13])/2*1
X=(-4+-SQRT[16-52])/2
X=(-4+-SQRT-36)/2
X=(-4+-6i)/2
X=-4/2+-6i/2
X=-2+-3i ANS.
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5a^2-6a+1=0
b^2-4ac
-6^2-4*5*1=36-20=16 this equation has 2 real number solutions: rational.
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To find the x intercepts set this equationto zero.
f(x)=-x^2+1
0=-x^2+1
x^2=1
x=sqrt1
x=+-1 ans. 
x intercepts are (1,0) (-1,0) 
{{{ graph( 300, 200, -6, 5, -10, 10, -x^2 +1) }}} (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, -x^2 +1).