If the sum of the two roots of the equation 4x3+16x2-9x-36=0 is zero, then the roots are

Given equation 4x3+16x2-9x-36=0,Putting x=-4⇒-4×64+256+36-36=0Hence x=-4 is a root of the equationNow reduced equation is 4x2(x+4)-9(x+4)=0⇒(x+4)(4x2-9)=0⇒x=-4, x=±32Thus roots are -4, -32, 32