Question

. Rezolvaţi în mulţimea Z ecuaţia:
a) x + 7 = 3; b) 6 − x =15; c) − 2 − x = −5;
d) 16 − x = −4; e) 11− x =14; f) − x + 4 = −9.

Answer 1

$a)x + 7 = 3$

$x = 3 - 7$

$x = - 4 \: \in \: \mathbb{Z}$

$b)6 - x = 15$

$- x = 15 - 6$

$- x = 9 \: | \times ( - 1)$

$x = - 9 \: \in \: \mathbb{Z}$

$c) - 2 - x = - 5$

$- x = - 5 + 2$

$- x = - 3 \: | \times ( - 1)$

$x = 3 \: \in \: \mathbb{Z}$

$d)16 - x = - 4$

$- x = - 4 - 16$

$- x = - 20 \: | \times ( - 1)$

$x = 20 \: \in \: \mathbb{Z}$

$e)11 - x = 14$

$- x = 14 - 11$

$- x = 3 \: | \times ( - 1)$

$x = - 3 \: \in \: \mathbb{Z}$

$f) - x + 4 = - 9$

$- x = - 9 - 4$

$- x = - 13 \: | \times ( - 1)$

$x = 13 \: \in \: \mathbb{Z}$