Help PLease with Math?

Question

Calculate the discriminant and use it to determine how many real-number roots the equation has.

1. x^2 - x + 2 =0
A. 9; two real-number roots
B. 7; two real-number roots
C. -7; no real-number roots
D. -9; no real-number roots

2. 3x^2 - 6x + 3 = 0
A. 72; two real-number roots
B. 36; two real-number roots
C. 0; one real-number root
D. -36; no real-number roots

Answer 1

x = (1 +/- sqrt(1 - 8))/2
C

x = (6 +/- sqrt(36 - 36))/6
C

Answer 2

ax^2 +bx + c = 0

D = B^2 - 4ac (discriminant)
D>0 = two real roots
D=0 = one root
D<0 = no real roots, 2 complex roots

(-1)^2 -4*1*2 = 1-8 = -7 (No real roots)
(-6)^2-4*3*3 = 36-36 = 0 (One real root)

Answer 3

1 and 2 are both (C)