Question

Помогите с заданиями 6,7,8,9,10. Даю 57 балов

Answer 1

6) 5mx -4by + 4my - 5bx = (5mx + 4my) - (4by + 5bx) = m(5x + 4y) - b(4y + 5x) = (5x + 4y)(m - b)

(5 * (- 6) + 4 * 7)(9  - 8) = (- 30 + 28) * 1 = - 2

7) (5 - t)(- t - 5) - (4 + t)² = (t - 5)(t + 5) - (4 + t)² = t² - 25 - 16 - 8t - t² = - 8t - 41

$8)\frac{80,25^{2}-79,75^{2}}{0,4^{2}+1,28+1,6^{2}}=\frac{(80,25-79,75)(80,25+79,75)}{(0,4+1,6)^{2}}=\frac{0,5*160}{2^{2}}=\frac{80}{4}=20$

9) 49 - 9n² +6mn - m² = - [( 9n² - 6mn + m² ) - 49] = - [(3n - m) - 7²] =

= - (3n - m - 7)(3n - m + 7)

10) (x - b + 1)² + 2(b - x - 1)(x + b + 1) + (x + b + 1)² = (x - b + 1)² -

- 2(x - b + 1)(x + b + 1) + (x + b + 1)² = [(x - b + 1) - (x + b + 1)]² =

= (x - b + 1 - x - b - 1)² = (- 2b)² = 4b²

4 * 0,4² = 4 * 0,16 = 0,64