Verified answer

You've done just fine so far, except you lost the x in the second part (it's still under the square root...should be xy instead of zy)...combine the stuff that is out of the square root...then combine all the stuff inside the same square root.

I'll do an alternative way...combine them under one square root and *then* solve...so:

Since both are square roots...they can live together under one happy square root roof...then combine like terms...finally take out the perfect squares:

√x^3y^4z * xyz^4

√(x^3 * x)(y^4 * y)(z * z^4)

√(x^4)(y^4 * y)(z * z^4)

x^2y^2z^2√yz

This is the same thing you got if you combine all the "out" stuff and all the "in" stuff:

xy^2z^2√xyxz

xy^2z^2√x^2yz

xxy^2z^2√yz

x^2y^2z^2√yz

Hope that helps!