Math Problem Statement

Solve the equation using substitution and a Z equation

Solve the equation using substitution and a 'z equation': (x + 2)^2 - 4(x + 2) + 3 = 0

Solution

Let's solve the given equation step-by-step using substitution.

Problem

The equation given is: (x+2)24(x+2)+3=0(x + 2)^2 - 4(x + 2) + 3 = 0

We are asked to use substitution, defining z=x+2z = x + 2.

Steps to Solve

  1. Substitute z=x+2z = x + 2 into the equation:

    • This substitution turns the equation into: z24z+3=0z^2 - 4z + 3 = 0
  2. Solve the equation in terms of zz:

    • Now we have a quadratic equation in zz: z24z+3=0z^2 - 4z + 3 = 0
    • To solve this quadratic equation, we can factor it: (z3)(z1)=0(z - 3)(z - 1) = 0
    • Setting each factor equal to zero gives: z3=0z=3z - 3 = 0 \quad \Rightarrow \quad z = 3 z1=0z=1z - 1 = 0 \quad \Rightarrow \quad z = 1
  3. Back-substitute to find xx:

    • Since z=x+2z = x + 2, we can substitute back for each value of zz:
      • If z=3z = 3: x+2=3x=32=1x + 2 = 3 \quad \Rightarrow \quad x = 3 - 2 = 1
      • If z=1z = 1: x+2=1x=12=1x + 2 = 1 \quad \Rightarrow \quad x = 1 - 2 = -1

Solution

The values of xx are: x=1andx=1x = 1 \quad \text{and} \quad x = -1

Would you like more details on the factoring or any other part of the solution?


Here are five related questions to deepen your understanding:

  1. How can you determine the correct substitution variable in similar problems?
  2. What other methods can be used to solve a quadratic equation aside from factoring?
  3. Why does back-substitution work when solving equations with substitution?
  4. How can you verify the solutions you found for xx are correct?
  5. Can you use this substitution technique in equations that aren’t quadratic?

Tip: Always double-check your solutions by substituting them back into the original equation to ensure they satisfy it.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Substitution Method

Formulas

Quadratic equation formula: ax^2 + bx + c = 0

Theorems

Factoring method for solving quadratics

Suitable Grade Level

Grade 10