1) сомнительный
4*(49^(1/2)*Loq(7) 9 - Loq(7) 2) =
4*((7²)^(1/2) *Loq(7) 3² - Loq(7) 2) =4*(7^(2*1/2)*2Loq(7) 3 - Loq(7) 2) =
4*(14Loq(7) 3 - Loq(7) 2) . * * * || 4*(Loq(7) (3^14)/2) ) * * *
2) |x-28| -2|x| =4 ;
2|x| +4 =|x-28| ;
[ { -∞ { 0≤x< 28 ;2x +4 = -(x-28),
{ x ≥28 ; 2x+4 = x-28.
[ x= - 24 , x= 8,
ответ : { - 24 ; 8}
3) (4/9)^(x)*(27/8)^(x-1) ≥ Lq4/Lq8 ;
(2/3)^(2x)*(2/3)^(-3(x-1)) ≥ 2Lq2/3Lq2;
(2/3)^(2x -3(x-1)) ≥2/3 ;
(2/3)^(3 -x) ≥(2/3)^1 т.к. 0<2/3<1,то ; <br>3 -x ≤ 1 ⇒x ≥2.
ответ : x ∈ [2 ;∞).
4) (ctqα - tqα)*tq2α =(1/tqα -tqα)* 2tqα/(1-tq²α) =(1-tq²α)/tqα *2tqα/(1-tq²α) =2.