Math Problem Statement

∣x+7∣+2= 4x

Solution

We have the equation:

x+7+2=4x|x + 7| + 2 = 4x

Step 1: Isolate the absolute value expression

Subtract 2 from both sides:

x+7=4x2|x + 7| = 4x - 2

Step 2: Consider both cases for the absolute value

Case 1: x+70x + 7 \geq 0

In this case, the absolute value function can be removed without changing the expression:

x+7=4x2x + 7 = 4x - 2

Solve for xx:

7+2=4xx7 + 2 = 4x - x 9=3x9 = 3x x=3x = 3

Case 2: x+7<0x + 7 < 0

In this case, the absolute value function changes the sign of the expression inside:

(x+7)=4x2-(x + 7) = 4x - 2

Simplify:

x7=4x2-x - 7 = 4x - 2

Solve for xx:

7+2=4x+x-7 + 2 = 4x + x 5=5x-5 = 5x x=1x = -1

Step 3: Check the validity of the solutions

  1. For x=3x = 3, check if x+70x + 7 \geq 0:

3+7=100(Valid)3 + 7 = 10 \geq 0 \quad \text{(Valid)}

  1. For x=1x = -1, check if x+7<0x + 7 < 0:

1+7=6(Invalid, since it’s positive)-1 + 7 = 6 \quad \text{(Invalid, since it's positive)}

Thus, the only valid solution is:

x=3\boxed{x = 3}


Would you like further clarification or details? Here are some related questions you might want to explore:

  1. What are the properties of absolute value functions?
  2. How do we handle equations involving inequalities?
  3. How can you graph the solution to an absolute value equation?
  4. What are the steps to check the validity of solutions in absolute value equations?
  5. How would this problem change if the absolute value was on both sides?

Tip: Always check the conditions of the absolute value to avoid extraneous solutions!

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Math Problem Analysis

Mathematical Concepts

Algebra
Absolute Value Equations

Formulas

|x + 7| + 2 = 4x
x + 7 = 4x - 2
-(x + 7) = 4x - 2

Theorems

Absolute Value Theorem

Suitable Grade Level

Grades 9-10