IJIJ
Can you help me and explain why this approach is incorrect?
(x+2)^2 = |x+2|
Since modulus and square is always positive,
(x+2)^2 - (x+2)=0
(x+2)(x+2-1)=0
(x+2)(x+1)=0
x=-2, -1
IJIJ Your statement "(x+2)2 - (x+2) = 0" assumes that \(|x+2| = (x+2)\) for all values of \(x\). This is the key misconception!
Why This Doesn't Work:While both \((x+2)^2\) and \(|x+2|\) are indeed non-negative, they are
different functions:
- \(|x+2| = (x+2)\) only when \(x+2 \geq 0\)
- \(|x+2| = -(x+2)\) when \(x+2 < 0\)
The Correct Approach:We must consider both cases for the absolute value:
Case 1: When \(x+2 \geq 0\) (i.e., \(x \geq -2\))
\(|x+2| = (x+2)\)
So: \((x+2)^2 = (x+2)\)
\((x+2)^2 - (x+2) = 0\)
\((x+2)(x+2-1) = 0\)
\((x+2)(x+1) = 0\)
This gives \(x = -2\) or \(x = -1\)
Both satisfy \(x \geq -2\), so both are valid! ✓
Case 2: When \(x+2 < 0\) (i.e., \(x < -2\))
\(|x+2| = -(x+2)\)
So: \((x+2)^2 = -(x+2)\)
\((x+2)^2 + (x+2) = 0\)
\((x+2)(x+2+1) = 0\)
\((x+2)(x+3) = 0\)
This gives \(x = -2\) or \(x = -3\)
Only \(x = -3\) satisfies \(x < -2\), so it's valid! ✓
Solutions: \(x = -3, -2, -1\)
Product: \((-3) \times (-2) \times (-1) = -6\)