Question

помогите с 29 номером 38 баллов
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Answer 1

Ответ:

Объяснение:

1) 20x-80-51+34x=58+27x

54x-131=58+27x

54x-27x=131+58

27x=189

x=189/27=7

2) -4,5(3x+2)+1,6(5-4x)=3,1x+1,3

-13,5x-9+8-6,4x=3,1x+1,3

-19,9x-1=3,1x+1,3

-19,9x-3,1x=1+1,3

-23x=2,3

x=2,3:(-23)=-0,1

3) 5/21 (7-3x)- 4/35 (5x+7)=2/15 -2/7

5/3 -5/7 x- 4/7 x- 4/5=2*7/(7*15) -15*2/(15*7)

5*5/(5*3) -3*4/(3*5) -9/7 x=(14-30)/105

(25-12)/15 -9/7 x=-16/105

9/7 x=7*13/(7*15) +16/105

9/7 x=(91+16)/105

9/7 x=107/105

x=107/105 *7/9=107/(15*9)=107/135

4) 3²/4² (2^5 +x)+ 7/12 (36-x)=5/4² x-7

(9*2^5)/2^4 +9/4² x+ 7*3- 7/12 x=5/4² x-7

5/4² x- 9/4² x+7/12 x=18+21+7

-1/4 x+ 7/12 x=46

(-3+7)/12 x=46

1/3 x=46

x=46*3=138

Answer 2

$1)\; \; 20(x-4)-17(3-2x)=58+3^3\, x\\\\20x-80-51+34x=58+27x\\\\54x-27x=58+131\\\\27x=189\\\\x=7\\\\2)\; \; -4,5(3x+2)+1,6(5-4x)=3,1x+1,3\\\\-13,5x-9+8-6,4x=3,1x+1,3\\\\-19,9x-3,1x=1,3+1\\\\-23x=2,3\\\\x=-0,1\\\\3)\; \; \frac{5}{21}\, (7-3x)-\frac{4}{35}\, (5x+7)=\frac{2}{15}-\frac{2}{7}\\\\\frac{5}{3}-\frac{5}{7}x-\frac{4}{7}x-\frac{4}{5}=\frac{14-30}{15\cdot 7}\\\\-\frac{9}{7}x=-\frac{16}{105}-\frac{5}{3}+\frac{4}{5}\\\\-\frac{9}{7}x=\frac{-16-5\cdot 35+4\cdot 21}{105}\\\\-\frac{9}{7}x=-\frac{107}{105}$

$x=\frac{107}{105}\cdot \frac{7}{9}\\\\x=\frac{107}{15\cdot 9}\\\\x=\frac{107}{135}\\\\4)\; \; \frac{3^2}{4^2}\, (2^5+x)+\frac{7}{12}\, (36-x)=\frac{5}{4^2}x-7\\\\9\cdot 2+\frac{9}{16}x+7\cdot 3-\frac{7}{12}x=\frac{5}{16}x-7\\\\\frac{9}{16}x-\frac{7}{12}x-\frac{5}{16}x=-7-18-21\\\\\frac{27-28-15}{48}\, x=-46\\\\-\frac{16}{48}\, x=-46\\\\x=\frac{46\cdot 48}{16}\\\\x=138$