Question 377975
{{{3i(2 + 5i)}}} simplifies to {{{6i + 15i^2}}} or {{{-15 + 6i}}} --> x = -15.

The square root of a negative number is not defined on the real axis. This is why mathematicians created the number {{{i = sqrt(-1)}}}. For example, {{{sqrt(-9) = 3i}}}.