Math Problem Statement

Solve the system of linear equations using elimination.

10x + 7y = 12 8x + 7y = 18

Solution

To solve the system of linear equations using the elimination method, we have the following equations:

  1. 10x+7y=1210x + 7y = 12
  2. 8x+7y=188x + 7y = 18

Step 1: Eliminate one variable

Notice that both equations have the same 7y7y term. We can eliminate yy by subtracting the second equation from the first. This will cancel out yy:

(10x+7y)(8x+7y)=1218(10x + 7y) - (8x + 7y) = 12 - 18

Simplifying the equation:

(10x8x)+(7y7y)=6(10x - 8x) + (7y - 7y) = -6

2x=62x = -6

Step 2: Solve for xx

Now solve for xx:

x=62=3x = \frac{-6}{2} = -3

Step 3: Substitute x=3x = -3 into one of the original equations

Substitute x=3x = -3 into the first equation, 10x+7y=1210x + 7y = 12:

10(3)+7y=1210(-3) + 7y = 12

30+7y=12-30 + 7y = 12

Step 4: Solve for yy

Now solve for yy:

7y=12+307y = 12 + 30

7y=427y = 42

y=427=6y = \frac{42}{7} = 6

Final Answer:

The solution to the system is:

x=3,y=6x = -3, \quad y = 6

Want more details? Or have any questions?

Here are five related questions:

  1. What is the graphical interpretation of solving a system of linear equations by elimination?
  2. How can the substitution method be used to solve this system instead of elimination?
  3. What would happen if the coefficients of yy in both equations were different?
  4. How can you solve a system of equations with three variables using the elimination method?
  5. How can we check if our solution is correct using substitution?

Tip: Always check your solution by substituting the values back into the original equations to verify they satisfy both equations!

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Math Problem Analysis

Mathematical Concepts

Linear Equations
Elimination Method
Systems of Equations

Formulas

Elimination method: Subtract or add equations to eliminate one variable

Theorems

Linear equations theorem
Elimination theorem

Suitable Grade Level

Grades 8-10