[tex]E(x) = 4 {x}^{2} - 4x + 1 + 2(2 {x}^{2} + 2x - x - 1) + {x}^{2} + 2x + 1 = 4 {x}^{2} - 4x + 1 + 4 {x}^{2} + 4x - 2x - 2 + {x}^{2} + 2x + 1 = 9 {x}^{2} [/tex]
9x^2=3•3•×^2=> 9x^2 este multiplu de 3=> 9x^2 se divide cu 3=> E(×) se divide cu 3
[tex]a = E( \frac{1}{ \sqrt{x}3 }) \\ b = E(4) \\ E( \frac{1}{ \sqrt{x}3 } ) = 9 \times { \frac{1}{ \sqrt{x}3 } }^{2} = 9 \times \frac{1}{9x} = \frac{1}{x} \\ a = \frac{1}{x} \\ E(4) = 9 \times {4}^{2} = 9 \times 16 = 144 \\ \sqrt{a \times b} = \sqrt{ \frac{1}{x} \times 144} = \sqrt{ \frac{144}{x} } = \frac{12}{ \sqrt{x} } = \frac{12 \sqrt{x} }{x} [/tex]
