Math Problem Statement

Use the elimination method to solve the system of equations: 2x + 3y = 8 and x - y = 9. Options: (7, -2), (7, 2), (2, 4), (6, 10).

Solution

The question asks you to solve the given system of equations using the elimination method:

  1. 2x+3y=82x + 3y = 8
  2. xy=9x - y = 9

Step 1: Make the coefficients of one variable equal

To eliminate xx, we multiply the second equation by 22, so the system becomes:

2x+3y=82x + 3y = 8 2x2y=182x - 2y = 18

Step 2: Subtract the equations

Subtract the second equation from the first:

(2x+3y)(2x2y)=818(2x + 3y) - (2x - 2y) = 8 - 18

Simplify:

5y=105y = -10

Solve for yy:

y=2y = -2

Step 3: Substitute y=2y = -2 into one of the original equations

Substitute y=2y = -2 into xy=9x - y = 9:

x(2)=9x - (-2) = 9

x+2=9x + 2 = 9

x=7x = 7

Final Answer:

The solution is (x,y)=(7,2)(x, y) = (7, -2).

Correct option: (7,2)(7, -2).

Would you like further details or have any questions?

5 Related Questions:

  1. How do you use substitution to solve a system of equations?
  2. What is the difference between elimination and substitution methods?
  3. How do you verify a solution to a system of equations?
  4. Can a system of equations have no solution or infinite solutions? Why?
  5. How is elimination useful for solving equations with fractions?

Tip:

Always double-check your work by substituting your solution back into both original equations!

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Math Problem Analysis

Mathematical Concepts

Linear Equations
Systems of Equations
Elimination Method

Formulas

Elimination technique: adding or subtracting equations to eliminate a variable

Theorems

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Suitable Grade Level

Grades 8-10