ADJ

complicated, simple
This can be shown by a simple equation
algebraic, mathematical

VERB + EQUATION

solve, work out
I could not find a way of solving the equation
satisfy
the range of values of x which would satisfy this equation

PREP

~ for
the equation for a straight line

PHRASES

a side of the equation
the numbers on the right-hand side of the equation

VERB + EQUATION

be a part of, come into, enter (into)
The availability of public transport is also part of the equation. Money also comes into the equation