Question

1 Rezolvați următoarele ecuații: a) 1,3 .x+2,73 = 2.(1,2x - 1); x 4 x+7 b) 2 9 6 5.X-1 2.x-3 1 c) + 10 6 3 +

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Answer 1

Răspuns:

)

1,3 × x + 2,73 = 2 × (1,2 × x - 1)

1,3x + 2,73 = 2,4x - 2

1,3 x - 2,4x = - 2 - 2,73

- 1,1x = - 4,73

x = - 4,73 : (-1,1)

x = 4,3

b)

\begin{gathered}\displaystyle \frac{x}2} \ + \ \frac{4}{9} \ = \ \frac{x + 7 }{6 } \ / \cdot 18 \\\\\\\displaystyle 9x \ + \ 8 \ = \ 3 \ \cdot \ (x \ + \ 7) \\\\\displaystyle 9x \ + \ 8 \ = \ 3x \ + \ 21 \\\\\\\displaystyle 9x \ - \ 3x \ = \ 21 \ - \ 8 \\ \\\displaystyle 6x = 13 \\\\\displaystyle x \ = \ \frac{13}{6}\end{gathered}

c)

\begin{gathered}\displaystyle \frac{5 \ \cdot \ x \ - \ 1}{10 } \ = \ \frac{2 \ \cdot \ x \ - 3 }{6} \ + \ \frac{1}{3} \ / \cdot 30 \\ \\\displaystyle 3 \ \cdot \ (5x \ - \ 1) \ = \ 5 \ \cdot \ (2x \ - \ 3) + \ 10 \\ \\\displaystyle 15x \ - \ 3 \ = \ 10x \ - \ 15 \ + \ 10\\ \\\displaystyle 15x\ - \ 10x\ \ = - 15 \ + \ 10 \ + \ 3 \\\\\displaystyle 5x \ = \ - 2 \\ \\\displaystyle x \ = \ - \ \frac{2}{5}\end{gathered}

10

5 ⋅ x − 1

=

6

2 ⋅ x −3

+

3

1

/⋅30

3 ⋅ (5x − 1) = 5 ⋅ (2x − 3)+ 10

15x − 3 = 10x − 15 + 10

15x − 10x =−15 + 10 + 3

5x = −2

x = −

5

2

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