Math Problem Statement

Solve the system by substitution: x - 5y = 10 -2x - 6y = -4

Solution

To solve the system of linear equations by substitution, we will go through the following steps:

Given: x5y=10x - 5y = 10 2x6y=4-2x - 6y = -4

Step 1: Solve for xx in terms of yy in the first equation.

From the equation x5y=10x - 5y = 10, we isolate xx: x=10+5yx = 10 + 5y

Step 2: Substitute x=10+5yx = 10 + 5y into the second equation.

Substitute this expression for xx in the second equation: 2(10+5y)6y=4-2(10 + 5y) - 6y = -4

Expanding this: 2010y6y=4-20 - 10y - 6y = -4 2016y=4-20 - 16y = -4

Step 3: Solve for yy.

Add 20 to both sides: 16y=16-16y = 16 Now, divide by -16: y=1y = -1

Step 4: Substitute y=1y = -1 back into the equation x=10+5yx = 10 + 5y to find xx.

x=10+5(1)x = 10 + 5(-1) x=105x = 10 - 5 x=5x = 5

Solution

The solution to the system is: x=5,y=1x = 5, \quad y = -1

Would you like further details on the steps, or do you have any questions?

Here are some related questions for further practice:

  1. How would you solve a system using the elimination method instead?
  2. What if both equations were set equal to each other instead of using substitution?
  3. How does the substitution method compare to graphing for solving systems?
  4. Could there be a scenario where substitution is not the ideal method?
  5. What happens if we rearrange both equations before starting the substitution?

Tip: In substitution, always isolate one variable first and substitute accurately to avoid calculation errors.

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Math Problem Analysis

Mathematical Concepts

Algebra
Systems of Linear Equations
Substitution Method

Formulas

Substitute x or y and solve for the other variable

Theorems

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Suitable Grade Level

Grade 8