How do we solve the following system of equations: x + 2y = 6, z + 3y + 2z = 7, 4 = 3x + 2y + 5z?

To solve the system of equations, we need to express it in a more manageable form:

  • Equation 1: x + 2y = 6
  • Equation 2: z + 3y + 2z = 7 simplifies to 3z + 3y = 7
  • Equation 3: 3x + 2y + 5z = 4

Next, from Equation 1, we can express x in terms of y:

x = 6 – 2y

Now, substituting this expression for x into Equation 3:

3(6 – 2y) + 2y + 5z = 4

This expands to:

18 – 6y + 2y + 5z = 4

Combining like terms gives:

18 – 4y + 5z = 4

Rearranging results in:

5z = 4y – 14

Now, expressing z in terms of y gives:

z = (4y – 14) / 5

Next, substituting z back into the second equation:

3((4y – 14) / 5) + 3y = 7

Multiplying through by 5 to eliminate the fraction yields:

3(4y – 14) + 15y = 35

Expanding gives:

12y – 42 + 15y = 35

Combining like terms results in:

27y – 42 = 35

Adding 42 to both sides gives:

27y = 77

Finally, solving for y results in:

y = 77 / 27

Now substituting this value for y back into the equations will give us the values for x and z:

1. Substitute y into x = 6 – 2y

x = 6 – 2(77 / 27) = 6 – (154 / 27) = (162 – 154) / 27 = 8 / 27

2. Substitute y back into z = (4y – 14) / 5

z = (4(77 / 27) – 14) / 5 = (308 / 27 – 378 / 27) / 5 = (-70 / 27) / 5 = -14 / 27

Thus, the solution to our equations is:

x = 8/27, y = 77/27, z = -14/27

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