mp+mq=r solve for m

Answer 1

if mp + mq = r then, m(p + q) = r and then m = r/(p + q)

Answer 2

Since m is a factor in both terms on the left side, we can factor it out.

m(p + q) = r

Now we have m multiplied by p + q. We need m by itself, so we divide by p + q.

m = r/(p + q)

Boom.