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6х-2(4х-1)=7 6х-8х-1=7 -2х=7-1 -2х=6 х=6:(-2) х=-3 всё
{4*3^x =12 ; 4^x*3^x =36 .
4*3^x =12 ;
3^x =3 ;
x =1 .
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но 4¹*3¹≠36 .
x ∈∅ .
* * * * * * *
{4*3^x =12 ; 4^x*3^y =36 ⇔{ 3^x =3¹ ; 3^y =36/(4^x) .
{ x =1 ; 3^y =9 . ⇒{ x =1 ; y =2 .