Question

Daca x€ [-3;4] si 2x-y+3=0 , atunci valorile lui y formeaza multimea ....
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Answer 1

Răspuns:

x ∈ {-3, -1, 1, 3, 5, 7, 9, 11}

Explicație pas cu pas:

2x - y + 3 = 0

y = 2x + 3

y = 2 * (-3) + 3 = -6 + 3 = -3

y =2 * (-2) + 3 = -4 + 3 = -1

y = 2 * (-1) + 3 = -2 + 3 = 1

y = 2 * 0 + 3 = 3

y = 2 * 1 + 3 = 2 + 3 = 5

y = 2 * 2 + 3 = 4 + 3 = 7

y = 2 * 3 + 3 = 6 + 3 = 9

y = 2 * 4 + 3 = 8 + 3 = 11

x ∈ {-3, -1, 1, 3, 5, 7, 9, 11}

Answer 2

$\it 2x-y+3=0 \Rightarrow y = 2x+3\ \ \ \ \ (*)\\ \\ x\in[-3,\ 4]|_{\cdot2} \Rightarrow 2x\in[-6,\ 8]|_{+3} \Rightarrow 2x+3\in[-3,\ 11]\stackrel{(*)}{\Longrightarrow}\ y\in[-3,\ 11]$