Question

Va rog mult, am nevoie de ajutor ! ​

Answer 1

Formulă :

$|-x|=|x|$

$a) |x| = 7 = > x \in \: \left\{-7,7\right\}$

$b) | - x| = | + 5|$

$| - x| = 5$

$| - x| = |x| = 5 = > x \in \: \left\{-5,5\right\}$

$c) |x + 3| = 0$

$x + 3 = 0$

$x = - 3$

$d) |x - 2| = 3$

$1)x - 2 = 3 = > x = 3 + 2 = 5$

$2) - x + 2 = 3$

$- x = 3 - 2$

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

$x = - 1$

$e) | - x + 4| = 9$

$1) - x + 4 = 9$

$- x = 9 - 4$

$- x = 5 \: | \times ( - 1)$

$x = - 5$

$2) - ( - x + 4) = 9$

$x - 4 = 9$

$x = 9 + 4$

$x = 13$

$f) | - 2 \times x| + 1 = 15$

$| - 2x| = 15 - 1$

$| - 2x| = 14$

$1) - 2x = 14 \: | \div ( - 2)$

$x = - 7$

$2) - ( - 2x) = 14$

$2x = 14 \: | \div 2$

$x = 7$