Question

(a - b ) elevado a 2 - c elevado a 2 quando a = 2/3 b = 1 c = -1 

Answer 1

(a - b ) ²  - c²
(a - b) × (a - b) - c²
a² - ab - ab + b² - c²
a² - 2ab +b² - c²

Substituindo pelos valores,  a = 2/3 b = 1 c = -1 :
a² - 2ab + b² - c²
 (2)² - 2. 2.1 + (1)² - (-1)²
 (3)        3

4 - 4  + (1)  - (+1)
9   3

4 - 4  + 1 - 1         mmc(3,9) = 9
9   3

4 - 12 + 9 - 9
        9

4 +9 - 12 - 9
      9

13 - 21
   9

- 8
  9

Answer 2

$\bigg(\frac{2}{3} \ - 1\bigg) ^{2} - ( - 1) ^{2} =$

$mmc \ (1, 3) = 3$

$\bigg(\frac{2 - 3}{3}\bigg) ^{2} - 1 =$

$\bigg(\frac{- 1}{3}\bigg) ^{2} - 1 =$

$\frac{1}{9} - 1 =$

$mmc (1, 9) = 9$

$\frac{1 - 9}{9} =$

$\frac{- 8}{9}$