Can you find the value of B from the below Mathematical equation?

Question

Answer 1

28 x 23 = 644 , so B = 2.

Answer 2

(10*B+8)*(10*B+3)=644=>100*(B^2)+110*B-620=0
=>10B^2+11B-62=0, A quadratic equation,=> two solutions, one real=>B=2, Another imaginary.