Question

O número desconhecido X é:

a) X+5=-8

b) X-4=-3

c) X-7=-7

d) X+9=-1

e)3X=12

f) -3=X+10

Answer 1

a) x +5 = -8 =>
    x = -8 -5 =>
    x = -13.

b)x -4 = -3 =>
   x = -3 -4 =>
   x = -7.

c)x -7 = -7 =>
   x = -7 +7 =>
   x = 0.

d)x +9 = -1 =>
   x = -1 -9 =>
   x = -10.

e)$3x=12$ =>
   $x=\frac{12}{2}$ =>
   $x=6$.

f)-3 = x +10 =>
  -3 -10 = x =>
  x = -13.

Answer 2

A)
$x+ 5 = - 8 \\ x= - 8 - 5 \\ x = - 13$

B)
$x - 4 = - 3 \\ x = - 3 + 4 \\ x = 1$

C)
$x - 7 = - 7 \\ x = - 7 + 7 \\ x = 0$

D)
$x + 9 = - 1 \\ x = - 1 - 9 \\ x = - 10$

E)
$3x = 12 \\ x = 12 \div 3 \\ x = 4$

F)
$- 3 = x + 10 \\ - x = 10 + 3 \\ - x = 13 \\ x = - 13$

Espero ter ajudado