Question

2 square root 32 - 5 square root 128

Answer 1

$2 \sqrt{32} -5 \sqrt{128} =2 \sqrt{16 \times 2} -5 \sqrt{64 \times 2} \\ =2 \times \sqrt{16} \times \sqrt{2} -2 \times \sqrt{64} \times \sqrt{2} \\ =2(4) \sqrt{2} -2(8) \sqrt{2} =8 \sqrt{2} -16 \sqrt{2} \\ =-8 \sqrt{2}$