If a(a - 4) = 21 and b(b - 4) = 21, where a ≠ b, then a + b =	Choose the correct option:
A) −48
B) −2
C) 4
D) 46
E) 48
a(a - 4) = 21 and b(b - 4) = 21   =&gt; a, b must be integers and if a is -3 or 7, b will be 7 and -3 respectively   =&gt; a+b = 4   Ans: 4
<result>C</result>
If a(a - 4) = 21 and b(b - 4) = 21, where a ≠ b, then a + b =