Step-by-step explanation:
By Geometric mean property:
[tex] {x} = \sqrt{12 \times 27} \\ = \sqrt{4 \times 3 \times {3}^{3} } \\ = \sqrt{ {2}^{2} \times {3}^{4} } \\ = 2 \times {3}^{2} \\ = 2 \times 9 \\ = 18 \\ \\ \huge \red { \boxed{\therefore \: x = 18}}[/tex]
