|x+5| ≤ |1-9x| Bantu

dikuadratin aja, terus dipindah ruas

(|x+5|)² ≤ (|1-9x|)²
(|x+5|)² - (|1-9x|)² ≤ 0
x²+10x+25 - (1 - 18x + 81x²) ≤ 0
x²+10x+25 - 1 +18x - 81x² ≤ 0
x²- 81x²+10x +18x+25-1 ≤ 0
-80x² + 28x + 24 ≤ 0
------------------------------ : 4
-20x²