Math Problem Statement

Solve the given system of linear equations using substitution and elimination methods.

Solution

Let's work through this step-by-step to help fill in the blanks.

Step 1

We have the equation: x3y=8x - 3y = -8 Solving for xx: x=8+3yx = -8 + 3y

Step 2

Now, substitute x=8+3yx = -8 + 3y into Equation 1 and Equation 3.

Substitute into Equation 1:

Original Equation 1: 2x4y+5z=302x - 4y + 5z = -30 Substituting x=8+3yx = -8 + 3y: 2(8+3y)4y+5z=302(-8 + 3y) - 4y + 5z = -30 Expanding this: 16+6y4y+5z=30-16 + 6y - 4y + 5z = -30 Combine terms: 2y+5z=142y + 5z = -14

Substitute into Equation 3:

Original Equation 3: 2x+2y5z=24-2x + 2y - 5z = 24 Substituting x=8+3yx = -8 + 3y: 2(8+3y)+2y5z=24-2(-8 + 3y) + 2y - 5z = 24 Expanding this: 166y+2y5z=2416 - 6y + 2y - 5z = 24 Combine terms: 4y5z=8-4y - 5z = 8

So, the equations we have after substitution are:

  • Equation 1: 2y+5z=142y + 5z = -14
  • Equation 3: 4y5z=8-4y - 5z = 8

Step 3

Rewrite these two equations as follows:

  • Equation 1: 2y+5z=142y + 5z = -14
  • Equation 3: 4y5z=8-4y - 5z = 8

Step 4

Now, add the two equations to eliminate zz and solve for yy: (2y+5z)+(4y5z)=14+8(2y + 5z) + (-4y - 5z) = -14 + 8 This simplifies to: 2y=6-2y = -6 Solving for yy: y=3y = 3


With y=3y = 3, we can substitute back to find xx and zz in further steps. Let me know if you want to continue or have questions on any of the above steps!

Related Questions

  1. How do you solve for zz once yy is found?
  2. What happens if there is no unique solution to this system?
  3. How can substitution be used in different types of systems of equations?
  4. Why is it useful to eliminate variables when solving systems of equations?
  5. What are alternative methods to solve this system besides substitution?

Tip

When solving systems of equations, carefully combine like terms to avoid errors, especially with signs.

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Math Problem Analysis

Mathematical Concepts

Systems of Linear Equations
Substitution Method
Elimination Method

Formulas

Substitute x = -8 + 3y
Eliminate z to find y

Theorems

Linear Combination

Suitable Grade Level

Grades 8-10