simplify sqrt(-108)-sqrt(-3)
Let's simplify: -108 --3
ⓘ In ℂ, the principal square root of a negative real number is i times the square root of its absolute value, because i² = -1: -108 = i×6×3, -3 = i×3
i×6×3 -i×3
ⓘ Like terms are grouped by adding their coefficients: i×6×3 -i×3 = 5i×3
▶Simplified form:   5i×3
The numeric value of: 5i×3 is:
5i×≈ 1.7321
▷ ≈ 8.6603i