Math Problem Statement

Find the solution to the system of equations: x + 3y = 7 and 2x + 4y = 8

1. Isolate x in the first equation:

2. Substitute the value for x into the second equation:

3. Solve for y:

4. Substitute y into either original equation:

5. Write the solution as an ordered pair:

x = 7 – 3y

2(7 – 3y) + 4y = 8

14 – 6y + 4y = 8

14 – 2y = 8

–2y = –6

y = 3

x + 3(3) = 7

Solution

Let’s solve step by step and confirm the solution:

Step 1: Isolate xx in the first equation

x+3y=7    x=73yx + 3y = 7 \implies x = 7 - 3y

Step 2: Substitute x=73yx = 7 - 3y into the second equation

2x+4y=8    2(73y)+4y=82x + 4y = 8 \implies 2(7 - 3y) + 4y = 8

Simplify: 146y+4y=8    142y=814 - 6y + 4y = 8 \implies 14 - 2y = 8

Step 3: Solve for yy

142y=8    2y=6    y=314 - 2y = 8 \implies -2y = -6 \implies y = 3

Step 4: Substitute y=3y = 3 into either original equation to find xx

Using the first equation: x+3(3)=7    x+9=7    x=2x + 3(3) = 7 \implies x + 9 = 7 \implies x = -2

Step 5: Write the solution as an ordered pair

The solution is: (x,y)=(2,3)(x, y) = (-2, 3)

Verification:

  • First equation: x+3y=2+3(3)=2+9=7x + 3y = -2 + 3(3) = -2 + 9 = 7 (Correct)
  • Second equation: 2x+4y=2(2)+4(3)=4+12=82x + 4y = 2(-2) + 4(3) = -4 + 12 = 8 (Correct)

The solution is consistent and valid.


Do you want more details or have any specific questions?

Here are 5 related questions to expand your understanding:

  1. How can you solve this system graphically?
  2. What happens if the system of equations has no solutions or infinite solutions?
  3. Can this system be solved using matrices or determinants (Cramer's Rule)?
  4. How does substitution differ from elimination in solving systems of equations?
  5. What real-world situations can be modeled by this system of equations?

Tip: Always verify your solution by substituting back into the original equations!

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Math Problem Analysis

Mathematical Concepts

Linear Equations
Systems of Equations
Substitution Method

Formulas

Substitute one equation into another: If x = 7 - 3y, substitute x into the second equation
Solving linear equations: 2(7 - 3y) + 4y = 8

Theorems

Properties of Equality
Substitution Principle

Suitable Grade Level

Grades 8-10