If x^2 - 9 = 0 and x > 0, which of the following must be equal to 0 ? Choose the correct choice.
A) x^2 - 9x	B) x^2 - 9x + 20	C) x^2 - 2x + 3	D) x^2 + 2x - 3	E) x^2 + 5x - 24
x^2-9 = 0   x= +3 or x = -3   if we substitute x= 3 in the equation x^2 +5x-24 = 9+15-24= 
<gadget id="calculator">9+15-24</gadget>
<output>0</output>
0   x^2 + 5x - 24 is also the answer
<result>E</result>
If x^2 - 9 = 0 and x > 0, which of the following must be equal to 0 ?