Math Problem Statement

Solve by substitution method 6x + 5y=3 and 7x + 8y= 10

Solution

To solve the system of linear equations using the substitution method, we'll follow these steps:

Given Equations:

  1. 6x+5y=36x + 5y = 3 (Equation 1)\quad \text{(Equation 1)}
  2. 7x+8y=107x + 8y = 10 (Equation 2)\quad \text{(Equation 2)}

Step 1: Solve one equation for one variable.

Let's solve Equation 1 for xx:

6x+5y=36x + 5y = 3 6x=35y6x = 3 - 5y x=35y6x = \frac{3 - 5y}{6} x=125y6x = \frac{1}{2} - \frac{5y}{6}

Step 2: Substitute the expression for xx into the other equation.

Substitute x=125y6x = \frac{1}{2} - \frac{5y}{6} into Equation 2:

7(125y6)+8y=107\left(\frac{1}{2} - \frac{5y}{6}\right) + 8y = 10

Step 3: Solve for yy.

Distribute and simplify:

7235y6+8y=10\frac{7}{2} - \frac{35y}{6} + 8y = 10

To eliminate the fractions, multiply the entire equation by 6:

6(7235y6+8y)=606\left(\frac{7}{2} - \frac{35y}{6} + 8y\right) = 60

2135y+48y=6021 - 35y + 48y = 60

Combine like terms:

13y+21=6013y + 21 = 60

Subtract 21 from both sides:

13y=3913y = 39

Now, solve for yy:

y=3913=3y = \frac{39}{13} = 3

Step 4: Substitute y=3y = 3 back into the expression for xx.

Now that we have y=3y = 3, substitute it into the expression for xx:

x=125(3)6x = \frac{1}{2} - \frac{5(3)}{6}

Simplify:

x=12156x = \frac{1}{2} - \frac{15}{6}

Convert 156\frac{15}{6} to 52\frac{5}{2}:

x=1252=152=42=2x = \frac{1}{2} - \frac{5}{2} = \frac{1 - 5}{2} = \frac{-4}{2} = -2

Final Answer:

The solution to the system of equations is: x=2,y=3x = -2, \quad y = 3

Would you like more details or have any questions?

Here are some related questions for further practice:

  1. How do you solve a system of equations using the elimination method?
  2. What are the benefits of using the substitution method over other methods?
  3. How can you verify the solution of a system of equations graphically?
  4. Can a system of linear equations have no solution or infinite solutions? If so, when?
  5. How do you interpret the solution of a system of equations in a real-world context?

Tip: Always substitute the solutions back into the original equations to check if they satisfy both equations.

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Math Problem Analysis

Mathematical Concepts

Linear Equations
Substitution Method

Formulas

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Theorems

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Suitable Grade Level

Grades 7-9