Question

Va rog la exercitiile 2,3.

Answer 1

Explicație pas cu pas:

2.

a)

$\frac{5}{9} = \frac{10}{3x} \\ 15x = 90 \\ x = \frac{90}{15} = 6$

b)

$\frac{5}{x} = \frac{16 \div 2^{2} }{12} \\ \frac{5}{x} = \frac{ {2}^{4} \div {2}^{2} }{12} \\ \frac{5}{x} = \frac{ {2}^{2} }{12} \\ \frac{5}{x} = \frac{4}{12} = \frac{1}{3} \\ 15 = x \\ = > x = 15$

3.

a)

$\frac{4}{6.3} = \frac{x}{9} \\ \frac{4}{ \frac{63}{10} } = \frac{x}{9} \\ \frac{40}{63} = \frac{x}{9} \\ 360 = 63x \\ x = \frac{360}{63} \\ x = \frac{40}{7}$

b)

$\frac{x + 3}{7} = \frac{x}{3} \\ 3(x + 3) = 7x \\ 3x + 9 = 7x \\ 3x = 7x - 9 \\ 3x - 7x = - 9 \\ - 4x = - 9 \\ x = \frac{9}{4}$

Sper ca te-am ajutat :)

Answer 2

Răspuns:

Explicație pas cu pas:

2).

a)   5/9 = 10/3x ⇒ 5 · 3 x = 9 · 10 → produsul mezilor = produsul extremilor

15 x = 90

x = 90 : 15

x = 6

Verific:   5/9 = 10/18 √   ( 10:2)/(18:2) = 5/9

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b)

5/x = (16:2²)/12  ⇒  5/x = (16:4)/12  ⇒  5/x = 4/12

⇔ 4 x = 5×12

4 x = 60

x = 60 : 4

x = 15

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3)

a)  4/3,6 = x/9

3,6 x = 4 × 9

x = 36/3,6   ( 36:36/10= 36 × 10/36 = 10)

x = 10

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b)

(x+3)/7 = x/3

7 x = 3 (x+3)

7 x = 3 x + 9

7 x - 3 x = 9

4 x = 9

x = 9/4

x = 2,25