Because the variables are independent, the common multiple must include each variable from both expression, and power of each variable must be not less then in every expression.

The least common multiple has the least possible power for each variable, i.e. maximum from both expressions.

For x, the least possible power is max(6,8)=8. For w max(4,5)=5. For u max(7,0)=7.

And the constant factors, 10 and 8, also require least common multiple. It is 40 (10=2*5, 8=2^3, LCM=2^3*5).

(the sign ^ is for the power (exponent))

So the answer is 40*x^8*w^5*u^7.

The greatest common factor, if you need it also, is 2*x^6*w^4 (take min of the powers).