Question

123 + 3x =300

Answer 1

\(123+3x=300\\ 3x=300-123\\ 3x=177\\ x=177:3\\ x=59.\)

Answer 2

\(123+3x=300\\ \Rightarrow3x=300-123\\ \Rightarrow3x=177\\ \Rightarrow x=\dfrac{177}{3}\\ \Rightarrow x=59\)