Question

7.8 плиз помогите.......... 1. 2.3.и 4
Найдите наибольшое и наименьшаее значение функции ​

Answer 1

$1) \: \: \: \: \: y = 1.5 + 6x$

$- 2 \leqslant x \leqslant 1$

$x = [ - 2 \: ; \: 1]$

$y = 1.5 + 6 \times ( - 2) = 1.5 - 12 = - 10.5$

$y = 1.5 + 6 \times 1 = 1.5 + 6 = 7.5$

$2) \: \: \: \: \: y = - 0.8x + 10$

$- 5 \leqslant x < 4$

$x = [ - 5 \: ; \: 3]$

$y = - 0.8 \times 5 + 10 = - 4 + 10 = 6$

$- 0.8 \times 3 + 10 = - 2.4 + 10 = 7.6$

$3) \: \: \: \: \: y = 11 - {x}^{2}$

$2 < x \leqslant 7$

$x = [1 \: ; \: 7]$

$y = 11 - {1}^{2} = 11 - 1 = 10$

$y = 11 - {7}^{2} = 11 - 49 = - 38$

$4) \: \: \: \: \: y = {x}^{2} + 5.4$

$- 3 \leqslant x \leqslant - 2$

$x = [ - 3 \: ; \: - 2]$

$y = {( - 3)}^{2} + 5.4 = 9 + 5.4 = 14.4$

${( - 2)}^{2} + 5.4 = 4 + 5.4 = 9.4$