Question

2.Multimea solutiilor ecuatiei |2x+5|=7 este...


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Answer 1

Răspuns:

S = {-6, 1}

Explicație pas cu pas:

|2x + 5| = 7

Cazul 1

2x + 5 = 7

2x = 7 - 5

2x = 2

x = 2 : 2

x = 1

Cazul 2

2x + 5 = -7

2x = -7 - 5

2x = -12

x = -12 : 2

x = -6

Answer 2

$\it |2x+5|=7\ \Rightarrow 2x+5=\pm7\ \Rightarrow \begin{cases}\it2x+5=-7|_{-5}\ \Rightarrow 2x=-12|_{:2}\ \Rightarrow x=-6\\ \\ \it 2x+5=7|_{-5}\ \Rightarrow 2x=2|_{:2}\ \Rightarrow x=1\end{cases}\\ \\ \\ S=\{-6,\ 1\}$