[tex]\it 1a)\ \left(\dfrac{1}{2}+\dfrac{1}{2}+\dfrac{1}{2}\right):\dfrac{3}{4} = \dfrac{1+1+1}{2}:\dfrac{3}{4} = \dfrac{3}{2} :\dfrac{3}{4} = \dfrac{3}{2}\cdot \dfrac{4}{3} = \dfrac{4}{2} =2 [/tex]
[tex]\it b)\ (7,5 + 2, 7):2 = 10,2:2 = 5,1
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c)\ 2,5\cdot10+4,5:2=25+2,25=27,25[/tex]
[tex]\it 2a)\ 7,2x+4,5=2|_{\cdot10} \Rightarrow 72x+45=20 \Rightarrow 72x = 20-45 \Rightarrow
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\Rightarrow 72x = -25 \Rightarrow x = - \dfrac{25}{72}[/tex]
[tex]\it b)\ -2,3x+4=-7|_{\cdot10} \Rightarrow -23x+40=-70 \Rightarrow 40+70 = 23x \Rightarrow
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\Rightarrow 110 = 23x \Rightarrow x = \dfrac{110}{23}[/tex]
