Consider Only the Discriminant $b ^ { 2 } - 4 a c$

Multiple Choice

Consider only the discriminant, $b ^ { 2 } - 4 a c$ to determine whether one real-number solution, two different real-number
solutions, or two different imaginary-number solutions exist.
- $$7 x ^ { 2 } = 21 x$$

A) 3
B) $10.5$
C) 7,3
D) 0,3