Respuesta :

Answer:

Step-by-step explanation:

Is called a letter that stands for the number

Answer:

Step-by-step explanation:

√10x - 1 = 7

Square both sides,

10x - 1 = 7²

10x - 1 =  49

10x = 49 + 1

10x = 50

x = 50/10

x=5