10. Найдите значение выражения (26)2(2-6)(2+6) прав

Ответ: -1.5

\begin{aligned} &(2 - b)^2 + (2 + b)(2 - b) = 4 - 4b + b^2 + 4 - b^2 = 8 - 4b\\&8 - 4b = -\frac{3}{4}\\&4b = 8 + \frac{3}{4} = \frac{35}{4}\\&b = \frac{35}{16}\\ &(2 - b)^2 + (2 + b)(2 - b) = -\frac{3}{4}; \quad b = -\frac{3}{4}\\&(2 - (-\frac{3}{4}))^2 + (2 + (-\frac{3}{4}))(2 - (-\frac{3}{4})) =\\&= (2 + \frac{3}{4})^2 + (2 - \frac{3}{4})(2 + \frac{3}{4}) =\\&= (\frac{11}{4})^2 + (\frac{5}{4})(\frac{11}{4}) =\\&= \frac{121}{16} + \frac{55}{16} = \frac{176}{16} = \frac{11}{1} = 11\\ &(2 - b)^2 + (2 - b)(2 + b) = -\frac{3}{4} \text{ при } b = -\frac{3}{4}\
&(2 - b)^2 + (2 - b)(2 + b) = 8 - 4b = -\frac{3}{4}\
&8 - 4b = -\frac{3}{4}\
&4b = 8 + \frac{3}{4} = \frac{32}{4} + \frac{3}{4} = \frac{35}{4}\
&b = \frac{35}{16}\\ &(2 - b)^2 + (2 - b)(2 + b) = -\frac{3}{4} \text{ при } b = \frac{35}{16}\
&(2 - \frac{35}{16})^2 + (2 - \frac{35}{16})(2 + \frac{35}{16}) = (\frac{32}{16} - \frac{35}{16})^2 + (\frac{32}{16} - \frac{35}{16})(\frac{32}{16} + \frac{35}{16}) =\\&= (-\frac{3}{16})^2 + (-\frac{3}{16})(\frac{67}{16}) = \frac{9}{256} - \frac{201}{256} = \frac{-192}{256} = -\frac{3}{4}\\ &b = -\frac{3}{4} = -0.75 \end{aligned}

Ответ: -1.5