1. V обозначает корень
Vc +1/Vd =V(0.36) +1/V(0.16) =V(0.6²) +1/V(0.4²) = 0.6 +1/0.4 =0.6 +2.5 =3.1
2. 25*(5^-1)^3 =25*(1/5)^3 =25 *1/125 =1/5 =0.2
4. умножим на V5
(V20 +V45)*V5 /(V5 *V5) =(V(20*5) +V(45*5)) /5 =(V(2²*5*5) +V(3²*5*5)) /5 =(2*5 +3*5) /5 =(10 +15)/5 =25/5 =5
5. b -4 = -(4 -b), тогда знаменатели одинаковые
(5b -20) /(4 -b) =5(b -4) /(-(b -4) = -5
6. (1/y -1/(x+y)) :x/y =(x+y -y)/y(x +y) *y/x =x/y(x +y) * y/x =xy /xy(x +y) =1/(x +y)
7. 2x² +3x -14 =0
D=9 +112 =121 =11²
x1 =(-3 -11)/4 = -3.5
x2 =(-3 +11)/4 =2
ответ: x= -3.5, x =2