If a(a + 7) = 18 and b(b + 7) = 18, where a ≠ b, then a + b = Pick:
A) −48	B) −5	C) 2	D) -7	E) 48
i.e. if a = 2 then b = -9   or if a = -9 then b = 2   But in each case a+b = -9+2 = -7   Answer: option -7
<result>D</result>
If a(a + 7) = 18 and b(b + 7) = 18, where a ≠ b, then a + b =