Question

If one of the roots of the equation 2$x^2$ + ax + 6 = 0 is 3, then find the value of a

Answer 1

If one root of the equation 2$x^2$ + ax + 6 = 0 is 3, then substitute x = 3 in the equation,

2$(3{)}^2$ + 3a +6 =0,

$\Rightarrow$ 18 + 3a + 6=0 ,

24 + 3a =0,

$\Rightarrow$ a = -8.