How can we solve the system of equations: 2x + 3y + z = 1, 3x + y + 2z = 12, and x + 2y + 3 = 5?

Solving the System of Equations

Let’s solve the given system of equations step-by-step:

  • Equation 1: 2x + 3y + z = 1
  • Equation 2: 3x + y + 2z = 12
  • Equation 3: x + 2y + 3 = 5

Step 1: Simplify Equation 3

First, let’s simplify Equation 3:

  • x + 2y = 5 – 3
  • x + 2y = 2

Step 2: Express x in terms of y

From the simplified Equation 3, we can express x in terms of y:

  • x = 2 – 2y

Step 3: Substitute x into Equation 1 and Equation 2

Next, we’ll substitute x = 2 – 2y into Equations 1 and 2.

Substituting into Equation 1:

  • 2(2 – 2y) + 3y + z = 1
  • 4 – 4y + 3y + z = 1
  • -y + z = 1 – 4
  • z = y – 3

Substituting into Equation 2:

  • 3(2 – 2y) + y + 2z = 12
  • 6 – 6y + y + 2z = 12
  • -5y + 2z = 12 – 6
  • 2z = 6 + 5y
  • z = 3 + (5/2)y

Step 4: Set the two equations for z equal to each other

We have two expressions for z:

  • z = y – 3
  • z = 3 + (5/2)y

Now we can set them equal:

  • y – 3 = 3 + (5/2)y
  • y – (5/2)y = 3 + 3
  • -3/2y = 6
  • y = -4

Step 5: Substitute y back to find x and z

Now, substitute y = -4 back into the expressions for x and z:

  • x: x = 2 – 2(-4) = 2 + 8 = 10
  • z: z = -4 – 3 = -7

Final Solution

The solution to the system of equations is:

  • x = 10
  • y = -4
  • z = -7

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