The difference between a number and its square is 72. What is the number?
A
18
B
19
C
30
D
9
Correct Answer: 9
Let, the number is = PP2 - P=72P2-P-72 =0P2-9P+8P-72=0P(P-9)+8(P-9) = 0(P-9)(P+8) = 0P-9 = 0P= 9 (Ans)