Using the discriminant, determine the number of real solutions. -4x^2+20x-25=0
a) no real solutions
b) one real solution
c) two real solutions

-4x² + 20x - 25 = 0
The discriminant Δ = b² - 4.a.c, where a= -4; b= 20 & c = - 25
Then Δ = (20)² - 4(-4)(-25)
Δ = 0 , since the discriminant = 0, we have one real solution (answer B)

For more info about Δ, If :
Δ > 0, then there are 2 real solutions, x' and x"

Δ = 0, then there are 2 equal real solutions, x' = x"

Δ < 0, then there are no solutions, or 2 imaginary values of x' and x"