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Rezolvati ecuatiile :
a) 2x+7=15
b) 3x-11=21
c) 5+2(x-1) =12
d) 3(x-3)-8=20
e) 15-4(x+1)=10
f )x- 2 supra 3 = 1pe langa si 1supra 15
g) 3 supra 4 -x = 1 supra 12
h) 7 supra 18 + x = 19 supra 15
i) 9 • x = 12
j) x • 4 supra 25 = 16 supra 5
k) 35 supra 24 : x = 2 , (3)
l ) 4x+5 = x + 13
m ) 11x + 17 = 2 x + 21
n) 3x - 1 supra 2 = 3 supra 7 - 4 x
o ) 3 supra 22 x - 1 supra 2 = 6 supra 55 + 1 supra 11 x
p) x supra 2 - x supra 3 = 7 supra 6

Răspuns :

Abc112
[tex]a)2x + 7 = 15[/tex]

[tex]2x = 15 - 7[/tex]

[tex]2x = 8[/tex]

[tex]x = \frac{8}{2} [/tex]

[tex]x = 4[/tex]

[tex]b)3x - 11 = 21[/tex]

[tex]3x = 21 + 11[/tex]

[tex]3x = 32[/tex]

[tex]x = \frac{32}{3} [/tex]

[tex]c)5 + 2(x - 1) = 12[/tex]

[tex]5 + 2x - 2 = 12[/tex]

[tex]2x = 12 - 5 + 2[/tex]

[tex]2x = 9[/tex]

[tex]x = \frac{9}{2} [/tex]

[tex]d)3(x - 3) - 8 = 20[/tex]

[tex]3x - 9 - 8 = 20[/tex]

[tex]3x - 17 = 20[/tex]

[tex]3x = 20 + 17[/tex]

[tex]3x = 37[/tex]

[tex]x = \frac{37}{3} [/tex]

[tex]e)15 - 4(x + 1) = 10[/tex]

[tex]15 - 4x - 4 = 10[/tex]

[tex] - 4x = 10 - 15 + 4[/tex]

[tex] - 4x = - 1 \: | \times ( - 1)[/tex]

[tex]4x = 1[/tex]

[tex]x = \frac{1}{4} [/tex]

[tex]f)x - \frac{2}{3} = 1\frac{1}{15} [/tex]

[tex]x - \frac{2}{3} = \frac{1 \times 15 + 1}{15} [/tex]

[tex]x - \frac{2}{3} = \frac{16}{15} [/tex]

[tex]15x - 10x = 16[/tex]

[tex]5x = 16[/tex]

[tex]x = \frac{16}{5} [/tex]

[tex]g) \frac{3}{4} - x = \frac{1}{12} [/tex]

[tex]9 - 12x = 1[/tex]

[tex] - 12x = 1 - 9[/tex]

[tex] - 12x = - 8 \: | \div ( - 4)[/tex]

[tex]3x = 2[/tex]

[tex]x = \frac{2}{3} [/tex]

[tex]h) \frac{7}{18} + x = \frac{19}{15} [/tex]

[tex]35 + 90x = 114[/tex]

[tex]9x = 114 - 35[/tex]

[tex]9x = 79[/tex]

[tex]x = \frac{79}{9} [/tex]

[tex]i)9x = 12[/tex]

[tex]x = \frac{12}{9} [/tex]

[tex]x = \frac{4}{3} [/tex]

[tex]j)x \times \frac{4}{25} = \frac{16}{5} [/tex]

[tex] \frac{4x}{25} = \frac{16}{5} [/tex]

[tex]4x \times 5 = 25 \times 16[/tex]

[tex]20x = 400[/tex]

[tex]x = \frac{400}{20} [/tex]

[tex]x = 20[/tex]

[tex]k) \frac{35}{24} \div x = 2.(3)[/tex]

[tex] \frac{35}{24} \times \frac{1}{x} = \frac{23 - 2}{9} [/tex]

[tex] \frac{35}{24x} = \frac{21}{9} [/tex]

[tex] \frac{35}{24x} = \frac{7}{3} [/tex]

[tex]24x \times 7 = 3 \times 35[/tex]

[tex]168x = 105[/tex]

[tex]x = \frac{105}{168} [/tex]

[tex]x = \frac{35}{56} [/tex]

[tex]x = \frac{5}{8} [/tex]

[tex]l)4x + 5 = x + 13[/tex]

[tex]4x - x = 13 - 5[/tex]

[tex]3x = 8[/tex]

[tex]x = \frac{8}{3} [/tex]

[tex]m)11x + 17 = 2x + 21[/tex]

[tex]11x - 2x = 21 - 17[/tex]

[tex]9x = 4[/tex]

[tex]x = \frac{4}{9} [/tex]

[tex]n)3x - \frac{1}{2} = \frac{3}{7} - 4x[/tex]

[tex]3x + 4x = \frac{3}{7} + \frac{1}{2} [/tex]

[tex]7x = \frac{6}{14} + \frac{7}{14} [/tex]

[tex]7x = \frac{6 + 7}{14} [/tex]

[tex]7x = \frac{13}{14} [/tex]

[tex]7x \times 14 = 13[/tex]

[tex]98x = 13[/tex]

[tex]x = \frac{13}{98} [/tex]

[tex]o) \frac{3}{22x} - \frac{1}{2} = \frac{6}{55} + \frac{1}{11x} [/tex]

[tex] \frac{3}{22} - \frac{x}{2} = \frac{6x}{55} + \frac{1}{11} [/tex]

[tex] \frac{15}{110} - \frac{55x}{110} = \frac{12x}{110} + \frac{10}{110} [/tex]

[tex]15 - 55x = 12x + 10[/tex]

[tex] - 55x - 12x = 10 - 15[/tex]

[tex] - 67x = - 5 \: | \times ( - 1)[/tex]

[tex]67x = 5[/tex]

[tex]x = \frac{5}{67} [/tex]

[tex]p) \frac{x}{2} - \frac{x}{3} = \frac{7}{6} [/tex]

[tex]3x - 2x = 7[/tex]

[tex]x = 7[/tex]

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