Math Problem Statement

Use substitution to determine the solution of the system of equations.

y = −2x − 7 2y − x = 1

A.	(−1,0)
B.	(212,−28)
C.	(−6,−52)
D.	(−3,−1)

Solution

To solve this system of equations using substitution, we can follow these steps:

  1. Substitute y=2x7y = -2x - 7 into the second equation.

    The system is: y=2x7y = -2x - 7 2yx=12y - x = 1

  2. Substitute yy from the first equation into the second equation: 2(2x7)x=12(-2x - 7) - x = 1

  3. Simplify the equation: 4x14x=1-4x - 14 - x = 1 Combine like terms: 5x14=1-5x - 14 = 1 Add 14 to both sides: 5x=15-5x = 15 Divide by -5: x=3x = -3

  4. Substitute x=3x = -3 back into the first equation to find yy: y=2(3)7y = -2(-3) - 7 Simplify: y=67y = 6 - 7 y=1y = -1

  5. Solution: The solution to the system is (3,1)(-3, -1).

Answer:

D. (3,1)(-3, -1)

Would you like more details on any part of this solution?


Here are five related questions for further practice:

  1. How would you solve a similar system if the equations were y=3x+4y = 3x + 4 and y=x2y = x - 2?
  2. What is the elimination method, and how does it differ from substitution in solving systems?
  3. How can we verify that (3,1)(-3, -1) is the correct solution for this system?
  4. What are the steps if both equations in a system are given in terms of yy?
  5. How do we interpret a system of equations that has no solutions?

Tip: Always check your solution by substituting the values back into both original equations. This helps confirm that your answer satisfies both conditions.

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Math Problem Analysis

Mathematical Concepts

Systems of Linear Equations
Substitution Method

Formulas

y = -2x - 7
2y - x = 1

Theorems

Substitution Method for Solving Systems

Suitable Grade Level

Grades 8-10