[tex] \frac{1}{x_1^2} + \frac{1}{x_2^2} = \frac{x_1^2+x_2^2}{x_1^2x_2^2}. relatia(1)\\ \\
x_1+x_2=- \frac{b}{a} =-4 \\ \\
P=x_1*x_2= \frac{c}{a} =-7 \\ \\
x1+x2=-4|^2, \\ \\
x_1^2+x_2^ 2+2x_1x_2=16 \\ \\
x_1^2+x_2^2=16-2P=16+14=30 \\ \\
In (1) \frac{30}{49} [/tex]
Mai verifica o data calculele.
