Math Problem Statement

y = 4x + 7

2x + 5y = - 31

Solution

We have the following system of linear equations:

  1. y=4x+7y = 4x + 7
  2. 2x+5y=312x + 5y = -31

We can solve this system using substitution, as the first equation already expresses yy in terms of xx.

Steps:

  1. Substitute y=4x+7y = 4x + 7 into the second equation 2x+5y=312x + 5y = -31: 2x+5(4x+7)=312x + 5(4x + 7) = -31

  2. Distribute 55 on the left-hand side: 2x+20x+35=312x + 20x + 35 = -31

  3. Combine like terms: 22x+35=3122x + 35 = -31

  4. Subtract 35 from both sides: 22x=313522x = -31 - 35 22x=6622x = -66

  5. Divide both sides by 22 to find xx: x=6622=3x = \frac{-66}{22} = -3

  6. Now substitute x=3x = -3 back into the first equation y=4x+7y = 4x + 7 to find yy: y=4(3)+7=12+7=5y = 4(-3) + 7 = -12 + 7 = -5

Solution:

x=3,y=5x = -3, \quad y = -5

Would you like more details or have any questions?

Here are 5 related questions you might consider:

  1. How would you solve the system using the elimination method?
  2. Can you graph both equations and identify their intersection point?
  3. What happens if you substitute y=5y = -5 directly into the second equation to check the solution?
  4. How does the substitution method work for nonlinear equations?
  5. How can you verify solutions of a system of equations?

Tip: When solving a system of equations, always substitute your solution back into both original equations to verify correctness.

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Math Problem Analysis

Mathematical Concepts

Algebra
Linear Equations
Substitution Method

Formulas

y = 4x + 7
2x + 5y = -31

Theorems

Substitution Method for solving systems of linear equations

Suitable Grade Level

Grades 8-10