Answer :

To solve the given system of equations, we'll first simplify and rewrite the equations in a more manageable form.

The equations are:
[tex]\[ \left\{\begin{array}{l} \frac{2(x+1)+3=y}{3} \\ 3(x+5-y)+3x=12 \end{array}\right. \][/tex]

### First Equation

Starting with the first equation:
[tex]\[ \frac{2(x+1) + 3 = y}{3} \][/tex]

We can get rid of the fraction by multiplying both sides by 3:
[tex]\[ 2(x + 1) + 3 = y \][/tex]

Now, simplify inside the parentheses first:
[tex]\[ 2x + 2 + 3 = y \][/tex]

Combine like terms:
[tex]\[ 2x + 5 = y \][/tex]

This simplifies the first equation to:
[tex]\[ y = 2x + 5 \][/tex]

### Second Equation

Now, consider the second equation:
[tex]\[ 3(x + 5 - y) + 3x = 12 \][/tex]

First, distribute the 3:
[tex]\[ 3x + 15 - 3y + 3x = 12 \][/tex]

Combine like terms:
[tex]\[ 6x + 15 - 3y = 12 \][/tex]

Subtract 15 from both sides to isolate the terms involving [tex]\(x\)[/tex] and [tex]\(y\)[/tex]:
[tex]\[ 6x - 3y = -3 \][/tex]

Divide through by 3 to simplify:
[tex]\[ 2x - y = -1 \][/tex]

### Solving the System

We now have a system of two equations:
[tex]\[ \left\{\begin{array}{l} y = 2x + 5 \\ 2x - y = -1 \end{array}\right. \][/tex]

Substitute [tex]\(y = 2x + 5\)[/tex] into the second equation:
[tex]\[ 2x - (2x + 5) = -1 \][/tex]

Simplify inside the parentheses:
[tex]\[ 2x - 2x - 5 = -1 \][/tex]

This reduces to:
[tex]\[ -5 = -1 \][/tex]

Since [tex]\(-5\)[/tex] does not equal [tex]\(-1\)[/tex], this is a contradiction. Therefore, the system of equations has no solution. There are no values of [tex]\(x\)[/tex] and [tex]\(y\)[/tex] that satisfy both equations simultaneously.

Hence, the solution to this system of equations is:
[tex]\[ \boxed{\text{No solution}} \][/tex]