X^2+12x-30 (2x+7)(x^2+12x-30)-5x^2=2x^2(x+1)

(2x+7)(x²+12x-30)-5x²-2x³-2x²=0 (2x+7)(x²+12x-30)-x²(2x+7)=0 (2x+7)(x²+12x-30-x²)=0 (2x+7)(12x-30)=0 2x+7=0⇒2x=-7⇒x=-3,5 12x-30=0⇒12x=30⇒x=2,5

[latex](2x+7)( x^{2} +12x-30)-5 x^{2} =2 x^{2} (x+1) \\ 2 x^{3} +24 x^{2} -60x+7 x^{2} +84x-210-5 x^{2} =2 x^{3} +2 x^{2} \\ 2 x^{3} +26 x^{2} +24x-210-2 x^{3} -2 x^{2} =0 \\ [/latex] [latex] 26 x^{2} +24x-210-2 x^{2} =0 \\ 24 x^{2} +24x-210=0|:6 \\ [/latex] [latex]4 x^{2} -4x-35=0 \\ D=16+560=576 \ \ \sqrt{D} =24 \\ x_{1} = \frac{-4+24}{8} = \frac{20}{8} =2.5 \\ x_{2} = \frac{-4-24}{8} = \frac{-28}{8} =-3.5[/latex]