Math Problem Statement

3x+4y=-2, -3x-5y = 1 solve by substitution method

Solution

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

Given the system:

  1. 3x+4y=23x + 4y = -2
  2. 3x5y=1-3x - 5y = 1

Step 1: Solve one equation for one variable

Let's take the first equation and solve for xx in terms of yy.

From 3x+4y=23x + 4y = -2: 3x=24y3x = -2 - 4y x=24y3x = \frac{-2 - 4y}{3}

Step 2: Substitute this expression for xx into the second equation

Now substitute x=24y3x = \frac{-2 - 4y}{3} into the second equation 3x5y=1-3x - 5y = 1:

3(24y3)5y=1-3\left( \frac{-2 - 4y}{3} \right) - 5y = 1

Simplify: (3)×24y3=2+4y(-3) \times \frac{-2 - 4y}{3} = 2 + 4y So, the equation becomes: 2+4y5y=12 + 4y - 5y = 1 Simplify further: 2y=12 - y = 1 y=12-y = 1 - 2 y=1-y = -1 y=1y = 1

Step 3: Substitute y=1y = 1 back into the equation for xx

Now, substitute y=1y = 1 into the expression for xx: x=24(1)3=243=63=2x = \frac{-2 - 4(1)}{3} = \frac{-2 - 4}{3} = \frac{-6}{3} = -2

Solution:

The solution to the system is: x=2,y=1x = -2, \quad y = 1

Would you like more details or have any questions?

Here are 5 related questions:

  1. What if both equations had no solution (inconsistent system)?
  2. How would you solve this system using the elimination method?
  3. What happens if both equations describe the same line?
  4. How can you verify if the solution is correct?
  5. Can substitution be used when both equations are in standard form?

Tip: Always substitute your values back into the original equations to verify the solution is correct!

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Math Problem Analysis

Mathematical Concepts

Algebra
Systems of Linear Equations
Substitution Method

Formulas

Linear equation in two variables: ax + by = c

Theorems

Substitution method for solving systems of equations

Suitable Grade Level

Grades 8-10