Math Problem Statement

solve the given system using the elimination method: 4x+5y=2 x+2y=-2

Solution

To solve the given system of equations using the elimination method, follow these steps:

Step 1: Write down the system of equations.

  1. 4x+5y=24x + 5y = 2
  2. x+2y=2x + 2y = -2

Step 2: Multiply the second equation by a constant to align the xx-terms for elimination.

Since the coefficient of xx in the second equation is 1, and in the first equation it's 4, multiply the entire second equation by 4:

4(x+2y)=4(2)4(x + 2y) = 4(-2) This gives: 4x+8y=84x + 8y = -8

Now the system becomes:

  1. 4x+5y=24x + 5y = 2
  2. 4x+8y=84x + 8y = -8

Step 3: Subtract the first equation from the second to eliminate xx.

(4x+8y)(4x+5y)=82(4x + 8y) - (4x + 5y) = -8 - 2 Simplifying: 3y=103y = -10

Step 4: Solve for yy.

y=103y = \frac{-10}{3} Thus, y=103y = -\frac{10}{3}.

Step 5: Substitute the value of yy back into one of the original equations to solve for xx.

Substitute y=103y = -\frac{10}{3} into the second equation x+2y=2x + 2y = -2:

x+2(103)=2x + 2\left(-\frac{10}{3}\right) = -2

This simplifies to: x203=2x - \frac{20}{3} = -2

Multiply both sides by 3 to clear the fraction: 3x20=63x - 20 = -6

Add 20 to both sides: 3x=143x = 14

Now, divide by 3: x=143x = \frac{14}{3}

Final Solution: The solution to the system is: x=143,y=103x = \frac{14}{3}, \quad y = -\frac{10}{3}

Would you like further details or have any questions?

Related Questions:

  1. How would the elimination method change if both equations had the same coefficients for xx?
  2. Can you solve the same system using the substitution method?
  3. What is the graphical interpretation of the solution to this system?
  4. How does the elimination method compare to the matrix method for solving systems of equations?
  5. What happens if a system of equations has no solution or infinite solutions?

Tip: Always check your solution by substituting the values of xx and yy back into the original equations.

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Math Problem Analysis

Mathematical Concepts

Algebra
Systems of Equations
Elimination Method

Formulas

Linear equation: ax + by = c

Theorems

Elimination method theorem
Properties of equality

Suitable Grade Level

Grades 9-11