Answer:
[tex]\boxed{\sf \ \ \ x= 0 \ \ or \ \ x=-1/2 \ \ or \ \ x=5/2\ \ \ }[/tex]
Step-by-step explanation:
Hello,
[tex]12x^4-24x^3-15x^2=x^2(12x^2-24x-15)=0\\<=> x = 0 \ \ or \ \ 12x^2-24x-15=0[/tex]
0 is one of the solution, let's solve
[tex]12x^2-24x-15=0\\\\<=> 12x^2+6x-30x-15=0\\\\<=> 6x(2x+1)-15(2x+1)=0\\<=> (6x-15)(2x+1)=0\\<=> x = 15/6=5/2 \ \ or \ \ x = -1/2[/tex]
hope this helps