Question

Compute the value of the discriminant and give the number of real solutions of the quadratic equation. -2x^2+8x-1=0

Answer 1

Divide given eq. by -2, we get, x^2-4x+0.5=0. Here a=1, b=-4 and c=0.5. As disccriminant is given by sqrt(b^2-4*a*c).so sqrt((-4)^2-4*1*0.5)=3.7417.
Real roots are x1,2=-b+-discriminant
x1=-4+3.7417=-0.2583 and x2=-4-3.7417=-7.7417