Math Problem Statement

Solve using elimination.

–10x − 8y = 16 6x + 3y = –15

Solution

To solve the system of equations using the elimination method, we aim to eliminate one of the variables by manipulating the equations. The given system is:

10x8y=16(1)-10x - 8y = 16 \quad \text{(1)} 6x+3y=15(2).6x + 3y = -15 \quad \text{(2)}.

Step 1: Adjust coefficients to eliminate one variable

We decide to eliminate yy. To do so, we need to make the coefficients of yy equal (with opposite signs). The least common multiple of 88 and 33 is 2424.

  • Multiply (1) by 33 to make the coefficient of yy in the first equation 24-24: 3(10x8y)=3(16)30x24y=48(3).3(-10x - 8y) = 3(16) \quad \Rightarrow \quad -30x - 24y = 48 \quad \text{(3)}.

  • Multiply (2) by 88 to make the coefficient of yy in the second equation 2424: 8(6x+3y)=8(15)48x+24y=120(4).8(6x + 3y) = 8(-15) \quad \Rightarrow \quad 48x + 24y = -120 \quad \text{(4)}.

Step 2: Add the equations to eliminate yy

Add (3) and (4): (30x24y)+(48x+24y)=48+(120).(-30x - 24y) + (48x + 24y) = 48 + (-120). 18x=72.18x = -72.

Step 3: Solve for xx

x=7218=4.x = \frac{-72}{18} = -4.

Step 4: Substitute x=4x = -4 into one of the original equations

Substitute x=4x = -4 into (2): 6(4)+3y=15.6(-4) + 3y = -15. 24+3y=15.-24 + 3y = -15. 3y=9.3y = 9. y=93=3.y = \frac{9}{3} = 3.

Final Solution

The solution to the system is: x=4,y=3.x = -4, \quad y = 3.


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Related Questions

  1. How does the elimination method differ from substitution for solving systems of equations?
  2. Can this system of equations be solved graphically? If so, how would the solution look on a graph?
  3. What are some real-life applications of solving systems of equations?
  4. How do you determine the most efficient method (elimination, substitution, or matrix) for solving a system?
  5. How would the solution change if one of the equations were multiplied incorrectly during elimination?

Tip:

Always double-check your coefficients when multiplying equations to avoid errors during elimination.

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Math Problem Analysis

Mathematical Concepts

Algebra
Linear Equations
Systems of Equations
Elimination Method

Formulas

No specific formulas; involves manipulation of linear equations using addition, subtraction, and multiplication.

Theorems

Linear Combination Theorem

Suitable Grade Level

Grades 8-10