Please I need help the questions are in the image :)

1). x in (-oo:+oo)

(1/3)*(x-15) = 2/3 // - 2/3

(1/3)*(x-15)-(2/3) = 0

(1/3)*(x-15)-2/3 = 0

1/3*(x-15)-2/3 = 0

(1/3*3*(x-15))/3-2/3 = 0

1/3*3*(x-15)-2 = 0

x-17 = 0

(x-17)/3 = 0

(x-17)/3 = 0 // * 3

x-17 = 0

x-17 = 0 // + 17

x = 17

x = 17

2). Simplifying
3X + 1 = 3x + 5

Reorder the terms:
1 + 3X = 3x + 5

Reorder the terms:
1 + 3X = 5 + 3x

Solving
1 + 3X = 5 + 3x

Solving for variable 'X'.

Move all terms containing X to the left, all other terms to the right.

Add '-1' to each side of the equation.
1 + -1 + 3X = 5 + -1 + 3x

Combine like terms: 1 + -1 = 0
0 + 3X = 5 + -1 + 3x
3X = 5 + -1 + 3x

Combine like terms: 5 + -1 = 4
3X = 4 + 3x

Divide each side by '3'.
X = 1.333333333 + x

Simplifying
X = 1.333333333 + x

3). 12x=7x+5x

We move all terms to the left:

12x-(7x+5x)=0

We add all the numbers together, and all the variables

12x-(+12x)=0

We get rid of parentheses

12x-12x=0

We add all the numbers together, and all the variables

=0

x=0/1

x=0

(hope that helps you out)