1.Упростить выражения .2.Выполнить действия.

1)
а) $\sqrt{49c} - \sqrt{16c}+ \sqrt{25c} = 7 \sqrt{c} - 4 \sqrt{c} + 5 \sqrt{c} = 8\sqrt{c}$
b) $\sqrt{8m}-0.2 \sqrt{200m} +3 \sqrt{72m} = \sqrt{4*2} -0.2 \sqrt{100*2} +3 \sqrt{36*2} = 2 \sqrt{2}- 0.2*10 \sqrt{2} + 3*6\sqrt{2}= 2\sqrt{2}-2\sqrt{2}+18\sqrt{2}= 18 \sqrt{2}$
c) $(7 \sqrt{2} -\sqrt{98} + \sqrt{10})*2= 14\sqrt{2}-2\sqrt{49*2} +2\sqrt{10 }= 14\sqrt{2}-14\sqrt{2}+2\sqrt{10} = 2\sqrt{10}$

2)
a) $(1-\sqrt{2})(3+\sqrt{2})= 3+\sqrt{2}-3\sqrt{2}-( \sqrt{2})^{2} = 3-2\sqrt{2}-2=1-2\sqrt{2}$
b) $(3+ \sqrt{15})(\sqrt{15} -3) =( \sqrt{15} )^2 - 3^2= 15-9=6$
c) $(1+3 \sqrt{2})^2= 1^2+2*1*3\sqrt{2} +(3\sqrt{2} )^2= 1+6\sqrt{2} +18=19+6\sqrt{2}$