math word problem

Question

the equation x^2-0.8x+c=0 has one real solution. Use the discriminate to find the value of c

Answer 1

To Solve an equation of the form:

 

ax²+bx+c=0,

 

Discriminate D= (b²-4*a*c)  

 

For only a single real solution this D equals ZERO.

 

For the equation given: a=1, b=-0.8, c=c.

Discriminate D= (-0.8)²-(4*1*c) =0.

 

implies: 0.64-4c=0

 

implies: c=0.16

 

 

 

Answer 2

If Ax² + Bx + C = 0, then the discriminant is B²-4AC.  The equation has only one real solution when the discriminant is equal to 0.  

 

(-0.8)² - 4(1)(c) = 0

 

0.64 - 4c = 0

 

        -4c = -0.64

 

          c = 0.16

Answer 3

To have one real solution your discriminant has to equal 0

 

b^2 - 4ac = 0

 

(-.8)^2 - 4 (1) c = 0

 

.64 -4c = 0

 

.64 = 4c

 

c = .16