Respuesta:
a.) X + 14 = 20 B.) 2X + 3 = 21
X = 20 _ 14 2X = 21 _ 3
X = 6 2X = 18
X = 18/2
X = 9
C.) 3X + 9 = 39 D.) 2X + 4 = 6
3X = 39 _ 9 2X = 6 _ 4
3X = 30 2X = 2
X = 30/3 X = 2/2
X = 10 X = 1
E.) X + 3 = 18
X = 18 _ 3
X = 15
