SOLUTION: Ust the value of the discriminant to determine the number and type of roots for x^2-4x=21

Question 419087: Ust the value of the discriminant to determine the number and type of roots for x^2-4x=21
Answer by lwsshak3(11628) (Show Source): You can put this solution on YOUR website!
Use the value of the discriminant to determine the number and type of roots for x^2-4x=21
..
x^2-4x=21
x^2-4x-21=0
a=1, b=-4, c=-21
Discriminant=b^2-4*a*c
=(-4)^2*-4*1*-21
=16+84=100>0
ans:
Function has two real roots.
Note: because discriminant is a perfect square in this case, function is factorable like:
(x-7)(x+3)=0
See graph of function below:

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