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1. <span>((a+b)-(a-b))*((a+b)+(a-b))*(1/a+1/b) = (a+b-a+b)*(a+b+a-b)*(1/a+1/b) = 2a*2b*(a+b)/ab = 4a+4b = 4(a+b)</span>
2. (1,8<span>·3</span>)(10-3<span>·105</span>)=5,4
3. -164
4. 3,3
5. 6
6. А
7. Б
3х(х²+7х-1)=3хх²+3х·7х-3х=3х³+21х²-3х
2sinxcosx+√3sinx=0
sinx(2cosx+√3)=0
1)sinx=0
x=Пn
2)2cosx+√3=0
cosx=√3/2
x=+-5П/6+2Пn