If a(a - 9) = 10 and b(b -9) = 10, where a ≠ b, then a + b = Choose one.
A) −48	B) −2	C) 2	D) 9	E) 48
i.e. if a = -1 then b = 10   or if a = 10 then b = -1   But in each case a+b = -1+10= 
<gadget id="calculator">-1+10</gadget>
<output>9</output>
9   Answer: option 9
<result>D</result>
If a(a - 9) = 10 and b(b -9) = 10, where a ≠ b, then a + b =