Question

2✓72 - 3✓2 (✓49 - 5✓128) = ?

Answer 1

$\it 2\sqrt{72}-3\sqrt2(\sqrt{49}-5\sqrt{128}) = 2\sqrt{36\cdot2} -3\sqrt2(7-5\sqrt{64\cdot2})= \\\;\\ =12\sqrt2-3\sqrt2(7-40\sqrt2) =12\sqrt2-21\sqrt2+240 =240-9\sqrt2$

Answer 2

2√72-3√2(√48-5√128)=
=2×6√2-3√2(7-5×8√2)=
=12√2-21√2+240=
=240-9√2=
=3(80-3√2)