Math Problem Statement

2x+y=3 and -2x+5y=-9

Solution

We are given the system of equations:

  1. 2x+y=32x + y = 3
  2. 2x+5y=9-2x + 5y = -9

Let's solve this system using the elimination method.

Step 1: Add the two equations

Since the coefficients of xx are opposites ( 2x2x and 2x-2x ), we can add the two equations to eliminate xx.

(2x+y)+(2x+5y)=3+(9)(2x + y) + (-2x + 5y) = 3 + (-9) 0x+6y=60x + 6y = -6 6y=66y = -6 y=66=1y = \frac{-6}{6} = -1

Step 2: Substitute y=1y = -1 into one of the original equations

We'll substitute it into the first equation, 2x+y=32x + y = 3.

2x+(1)=32x + (-1) = 3 2x1=32x - 1 = 3 2x=3+1=42x = 3 + 1 = 4 x=42=2x = \frac{4}{2} = 2

Final Solution:

The solution to the system is: x=2,y=1x = 2, \quad y = -1

Let me know if you'd like more details or further explanation on any step!

Related Questions:

  1. How would the solution change if one of the coefficients in the second equation were different?
  2. Can you solve this system using the substitution method?
  3. What happens if you multiply both equations by a constant before solving?
  4. How can you graphically interpret the solution to this system?
  5. How would this process differ for a system with no solution or infinite solutions?

Tip: Elimination is a powerful method when one of the variables already has opposite coefficients!

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Math Problem Analysis

Mathematical Concepts

Algebra
Linear Equations
Systems of Equations
Elimination Method

Formulas

Linear equation: ax + by = c
Solution of two-variable linear systems

Theorems

Elimination Method for Solving Linear Systems

Suitable Grade Level

Grades 8-10