a)
√32 = √(16×2) = √16×√2 =4√2
b)
√50=√(25×2)=√25×√2=5√2
√72=√(36×2)=√36×√2=6√2
c)
3√32-12√50+8√72=3×4√2-12×5√2+8×6√2 =0
