We have a triangle: \(\displaystyle{A}{B}={3}{x}-{5}\), \(\displaystyle{B}{C}={2}{x}+{20}\), \(\displaystyle{A}{C}={4}{x}-{30}\)

An equilateral triangle has the property that all sides have the same length as well as the angles.

Thus, we can pull all the three sides equal to each other:

\(\displaystyle{4}{x}-{30}={3}{x}-{5}\)

\(\displaystyle{4}{x}-{3}{x}=-{5}+{30}\)

\(\displaystyle{x}={25}\), this is the answer

An equilateral triangle has the property that all sides have the same length as well as the angles.

Thus, we can pull all the three sides equal to each other:

\(\displaystyle{4}{x}-{30}={3}{x}-{5}\)

\(\displaystyle{4}{x}-{3}{x}=-{5}+{30}\)

\(\displaystyle{x}={25}\), this is the answer