Question

x+7 supra 5 = -1,8. 2(x-1)=(x-1)

Answer 1

x+7/5=-1,8
x=-1,8-7/5
x=9/5 -7/5
x=2/5

2x-2=x-1
2x-x=2-1
x=1

Answer 2

[tex]\it x+\dfrac{7}{5} =-1,8|_{\cdot10} \Longrightarrow 10x+14 =-18 \Longrightarrow 10x=-18-14 \Longrightarrow \\\;\\ \Longrightarrow 10x=-32 \Longrightarrow x =- \dfrac{32}{10} =-3,2[/tex]

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$\it 2\cdot(x-1) = x-1 \Longrightarrow x-1=0 \Longrightarrow x=1$

Am folosit egalitatea evidentă  2·0 = 0 și de aici, x-1 = 0