Răspuns :

Dianageorgiana794id

Răspuns:

a) 7x=12(⁴⁾1/3+³⁾1/4)

7x=12·7/12

simplifici 12 cu 12

7x=7=>x=1

________

b) 4x-75(1/5-1/5:5)

4x=75(1/5-1/5·1/5)

4x=75·(⁵⁾1/5-1/25)

4x=75·4/25

4x=3·4=>x=12:4=>x=3

________

c) 3·(x+1)=8·(0,75+6,75)

3x+3=8·7,5

3x=60-3=>x=57:3=>x=19

_________

d) 45 ·[0,2+0,(2)]=2x+1

0,(2)=2/9

0,2=2/10=1/5

45·(⁹⁾1/5+⁵⁾2/9)=2x+1

45·19/9=2x+1

5·19=2x+1

95-1=2x=>x=94:2=>x=47

_________

e) 992· [2⁴⁹(2²-2-1)]=8¹⁶·31x

992·(2⁴⁹·1)=8¹⁶·31x

992·2⁴⁹:8¹⁶=31x

2⁵·31·2⁴⁹:(2³)¹⁶=31x

31·2⁵⁺⁴⁹⁻⁴⁸=31x

31·2⁶=31x

31·64=31x=>x=64

am descompus 992=2⁵·31

_________

f) x·x=8·(14+4)

x²=8·56

x²=√3136=>x=56

inmultesti pe diagonala

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