|9+x|=4
Let's solve in ℝ: |9 + x| = 4
Since 4 ≥ 0, |9 + x| = 4 is equivalent to 9 + x = 4 or 9 + x = -4
Let's solve in ℝ: 9 + x = 4
ⓘ We subtract 9 from both sides
x = 4 -9
ⓘ Start from 4 and move back 9 on the number line, going below zero: 4 -9 = -5
Solution obtained: x = -5
Let's solve in ℝ: 9 + x = -4
ⓘ We subtract 9 from both sides
x = -4 -9
ⓘ Start from -4 and move back 9 more on the number line, away from zero: -4 -9 = -13
Solution found: x = -13
▶Solution:   x = { -13, -5 }