Zadanie 3
a)
7\sqrt5+\sqrt{20}=7\sqrt5+\sqrt{4*5}=7\sqrt5+2\sqrt5=9\sqrt5
b)
\sqrt{48}-\sqrt3=\sqrt{16*3}-\sqrt3=4\sqrt3-\sqrt3=3\sqrt3
c)
\sqrt{12}+\sqrt{27}=\sqrt{4*3}+\sqrt{9*3}=2\sqrt3+3\sqrt3=5\sqrt3
d)
\sqrt{45}-\sqrt{125}=\sqrt{9*5}-\sqrt{25*5}=3\sqrt5-5\sqrt5=-2\sqrt5
e)
0,2\sqrt{50}+0,8\sqrt{72}-0,3\sqrt{32}=0,2\sqrt{25*2}+0,8\sqrt{36*2}-0,3\sqrt{16*2}=
=0,2*5\sqrt2+0,8*6\sqrt2-0,3*4\sqrt2=\sqrt2+4,8\sqrt2-1,2\sqrt2=
=5,8\sqrt2-1,2\sqrt2=4,6\sqrt2
f)
3\sqrt{20}-\frac{1}{3}\sqrt{45}-5\sqrt{180}=3\sqrt{4*5}-\frac{1}{3}\sqrt{9*5}-5\sqrt{36*5}=
=3*2\sqrt5-\frac{1}{\not3^1}*\not3^1\sqrt5-5*6\sqrt5=6\sqrt5-\sqrt5-30\sqrt5=-29\sqrt5