Given: 4n2 + 25 = -20n, what is the value of the discriminant?

Question

Given: 4n2 + 25 = -20n, what is the value of the discriminant? i am so awful at this

Answer 1

Assuming that the quadratic equation is in the form:

 

ax^2 + bx + c, the discriminant is b^2 - 4ac

 

Let's put the equation into standard form where we start with

 

4n^2 + 25 = -20n

 

Rearranging gives us

 

4n^2 + 20n + 25 = 0; therefore a = 4, b = 20, and c=25

 

b^2 = 20*20 or 400

4ac = 4*4*25 = 400

 

b^2 -4ac  = 400 - 400 = 0

 

the discriminant is 0

 

this means that both roots are the same 

 

the roots are -r=b/2a = -20/(2*4) = -20/8 = -2.5