How do you find the discriminant and how many solutions does x^2 + 2x – 2 = 0 have?

2 Answers
Alan P. · Jim H
May 9, 2015

For an equation in the general form:
ax^2+bx+c=0
the discriminant is:
Delta = b^2 - 4ac
and
Delta { (<0 rarr "no Real solutions"), (=0 rarr "1 Real solution"), (>0 rarr "2 Real solutions"):}

For x^2+2x-2 = 0
Delta = (2)^2 - 4(1)(-2) = 12 >0
so this equation has 2 Real solutions

Gió
May 9, 2015

Your equation is in the form: ax^2+bx+c=0
Where:
a=1
b=2
c=-2
The discriminant is:
Delta=b^2-4ac=4-4(1*-2)=4+8=12>0
Now, if:
1] Delta>0 you have 2 distinct Real solutions;
2] Delta=0 you have two Real coincident solutions;
3] Delta<0 you have no Real solutions.

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