Task/26458817
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5.
(2 1/2)*(1 3/5) =0,4*(4-x) ;
5/2*8/5 =0,4*(4-x) ;
4 = 0,4*(4-x) ;
10 =4 - x ;
x = - 6 → А)
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6 .
a⁻⁹ / (a⁻²* a⁻⁵) - ? , если a =1/2
a⁻⁹ / (a⁻²* a⁻⁵) = a⁻⁹ / a⁻⁷ =a⁻² = || a =1/2|| =(1/2)⁻² =(2⁻¹)⁻² =2² =4 → D)
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7 . - - + - + +
3|x+3| - |5x-2| =3 ; ------------- (-3 )-----------(2/5) ---------------
a)
{ x < - 3 ; {x < - 3; {x < - 3;
{-3(x+3) +(5x-2) =3 .⇔ {2x = 14 .⇔ {x = 7 .⇒ x∈∅ .
б)
{ -3 ≤ x < 2/5 ; {-3 ≤ x < 2/5 ; {-3 ≤ x < 2/5 ;
{3(x+3) +(5x-2) =3 .⇔{8x = - 4 . ⇔ { x = -1/2. ⇒ x = -1/2.
в)
{ x ≥ 2/5 ; { x ≥ 2/5 ; { x ≥ 2/5 ;
{3(x+3) - (5x-2) =3 .⇔ {-2x = - 8.⇔{ x=4. ⇒ x = 4.
ответ : x = -1/2 , 4. → C )
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8 .
(x - 1) / 2 =(4+2x) / 3 ;
3(x - 1) =2(4+2x) ;
3x - 3 =8 + 4x ;
-3 -8 = 4x-3x ;
x = -11 → B)
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Удачи !