For this case we must solve the following equations:

We subtract 3x on both sides of the equation:

We subtract 7 on both sides of the equation:

We divide between 2 on both sides of the equation:

The second equation is:

We apply distributive property to the terms of parentheses:

We add common terms:

We add 10 to both sides of the equation:

We divide between 5 on both sides of the equation:

Third equation:

We apply distributive property to the terms within parentheses:

We add similar terms:

We subtract 6x on both sides of the equation:

We subtract 5 on both sides of the equation:

Answer:
