<em>when we solve the equation it will become x</em>² + 9x<em>= 0 now here a = 1 , b = 9 and c = 0 by using quaderatic formula x = -b +,-</em>√<em>b </em>²<em>- 4ac / 2a ( 2a is divided by all terms ) by putting values x = - 9 +,</em><em>- </em>√<em>81 / 2(1) ( </em>√<em>81 = 9)</em><em> x = -9 + 9 / 2 and x = -9 -9 /2 x = 0 and x = -18 /2 = -9 now there are two values for x one is- 9 and other is 0 so we put -9 as the value of x then answer will be zero..</em>