Answer:
[tex] \boxed{ - 7xy \sqrt{7x}} [/tex]
Step-by-step explanation:
[tex]\sf -2y\sqrt{28x^3} +3x \sqrt{63xy^2} - 3\sqrt{112x^3y^2} [/tex]
[tex] \: [/tex]
» Remove perfect nth powers and simplify.
[tex] \sf = -2y\sqrt{(7)(4)(x^2)(x)} +3x \sqrt{(7)(9)xy^2} - 3\sqrt{(7)(16)(x^2)(x)y^2} [/tex]
[tex] \sf = (-2y \cdot 2x) \sqrt{7x} +(3x \cdot 3y) \sqrt{7x} - (3 \cdot 4xy) \sqrt{7x} [/tex]
[tex]\sf = -4xy \sqrt{7x} + 9xy \sqrt{7x} - 12xy \sqrt{7x} [/tex]
[tex] \: [/tex]
» Combine radicals of the same index.
[tex]\sf = (-4xy + 9xy - 12xy) \sqrt{7x}[/tex]
[tex]\sf = -7xy \sqrt{7x} [/tex]
[tex] \: [/tex]
Thus,
[tex] \large\boxed{-2y\sqrt{28x^3} +3x \sqrt{63xy^2} - 3\sqrt{112x^3y^2} = - 7xy \sqrt{7x} } [/tex]
