Question

Упростить выражение: (3√2-1)(√8+1)

Answer 1

$(3 \sqrt{2}-1)( \sqrt{8} +1)=(3 \sqrt{2}-1)( \sqrt{2\cdot4} +1)=(3 \sqrt{2}-1)( 2\sqrt{2} +1)=\\ =3 \sqrt{2} \cdot 2 \sqrt{2}+ 3 \sqrt{2} \cdot 1 -1 \cdot 2 \sqrt{2}-1 \cdot 1 =6\cdot2+3 \sqrt{2} -2 \sqrt{2} -1=\\ =11+ \sqrt{2}$