Question

Sa se rezolve in Z ecuatiile,, ; a ) 9-2x=-21-7x ; b) 3( x+1)=11-x ; c)3x+2=3(x+1) ; d)5+x-2=-x+3 ; e ) 2(x+1)=10-x

Answer 1

$a)9 - 2x = - 21 - 7x$

$- 2x + 7x = - 21 - 9$

$5x = - 30$

$x = - \frac{30}{5}$

$x = - 6 \: \in \: \mathbb{Z}$

$b)3(x + 1) = 11 - x$

$3x + 3 = 11 - x$

$3x + x = 11 - 3$

$4x = 8$

$x = \frac{8}{4}$

$x = 2 \: \in \: \mathbb{Z}$

$c)3x + 2 = 3(x + 1)$

$3x + 2 = 3x + 3$

$3x - 3x = 3 - 2$

$0 = 1 = > ecuatia \: nu \: are \: sens$

$d)5 + x - 2 = - x + 3$

$x + x = 3 - 5 + 2$

$2x = - 2 + 2$

$2x = 0$

$x = \frac{0}{2}$

$x = 0 \: \in \: \mathbb{Z}$

$e)2(x + 1) = 10 - x$

$2x + 2 = 10 - x$

$2x + x = 10 - 2$

$3x = 8$

$x = \frac{8}{3} \: \notin \: \mathbb{Z}$