6 × 25 = (6 × 20) + (6 × n)
Simplify :)
150 = 120 + 6n
So, all we're really trying to do is solve for n, and to do so, we must get n isolated, or get it onto it's own side :)
So, to do so, we must subtract 120 from both sides.
150 - 120 = 6n
Simplify.
30 = 6n
Divide both sides by 6.
n = 30/6
n = 5
~Hope I helped!~