[tex]0.3 {x}^{2} \times ( - 5 {x}^{2} ) = - 1.5 \\ - 1.5 {x}^{4} = - 1.5 \\ {x}^{4} = - 1.5 \div ( - 1.5) \\ x {}^{4} = 1 \\ {x}^{4} - 1 = 0 \\( x {}^{2} - 1)( {x}^{2} + 1) = 0 \\ (x - 1)(x + 1)( {x}^{2} + 1) = 0 \\ {x}^{2} + 1 \: \: нет \: \: корней \\ x _{1} = 1 \\ x_{ 2 } = - 1[/tex]