Question

Solve the equation without the use of a calculator. please Help!!! Thank you!!!

Answer 1

$4x^4+15x=12x^3+5x^2 \\ 4x^4-12x^3-5x^2+15x=0\\ x(4x^3-12x^2-5x+15)=0\\ x(4x^2(x-3)-5(x-3))=0\\ x(4x^2-5)(x-3)=0\\ x(2x-\sqrt5)(2x+\sqrt5)(x-3)=0\\ x=0 \vee x=\dfrac{\sqrt5}{2} \vee x=-\dfrac{\sqrt5}{2} \vee x=3$