Solve the Absolute Value Equation System: |x+4| = |2x+20| with x > -10

Question

{x+4=2x+20xgt;10 \begin{cases} |x+4|=|2x+20| \\ x> -10 \end{cases}

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Consider the equation x+4=2x+20 |x+4| = |2x+20| .
  • Step 2: Break it down into two separate cases.

We'll address each case separately below:

Case 1: x+4=2x+20 x + 4 = 2x + 20

Simplifying gives:

x+4=2x+20 x + 4 = 2x + 20
4=2xx+20 4 = 2x - x + 20
4=x+20 4 = x + 20
Subtracting 20 from both sides, we get:
x=420 x = 4 - 20
x=16 x = -16 .

Since x>10 x > -10 is required, x=16 x = -16 is not valid.

Case 2: x+4=(2x+20) x + 4 = -(2x + 20)

Simplifying gives:

x+4=2x20 x + 4 = -2x - 20
Add 2x 2x to both sides:
x+2x+4=20 x + 2x + 4 = -20
3x+4=20 3x + 4 = -20
Subtract 4 from both sides:
3x=24 3x = -24
Divide by 3:
x=8 x = -8 .

Check: Since 8>10-8 > -10, this solution is valid.

Thus, the solution to the problem is x=8 x = -8 .

Answer

x=8 x=-8