Question

1.Упростить выражения .
2.Выполнить действия.

Answer 1

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

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