2x^4-5x^3-18x^2+45x=0

$2 x^{4} -5 x^{3} -18 x^{2} +45x=0 \\ 2 x^{4} -6 x^{3} +x ^{3} -3 x^{2} -15 x^{2} +45x=0 \\ 2 x^{3} (x-3)+ x^{2} (x-3)-15x(x-3)=0 \\ (2 x^{3} + x^{2} -15x)(x-3)=0 \\ x-3=0 \\ x_{1}=3 \\ 2 x^{3} + x^{2} -15x=0 \\ 2 x^{3} +6 x^{2} -5 x^{2} -15x=0 \\ 2 x^{2} (x+3)-5x(x+3)=0 \\ (2 x^{2} -5x)(x+3)=0 \\ x+3=0 \\ x_{2} =-3 \\ 2 x^{2} -5x=0 \\ x(2x-5)=0 \\ x_{3} =0 \\ 2x-5=0 \\ x_{4} =2,5$
Ответ: х=3; -3; 0; 2,5