1) BD = 10 cm
2) AE = 24 cm
(2b/5a-5a/2b)*(1/(2b+5a))=
(4b²-25a²)/10ab*(1/(2b+5a))=
((ab)²-(5a)²)/(10ab(2b+5a)=
(2b+5a)(2b-5a)/10ab(2b+5a)=
(2b-5a)/10ab= при: a=1/5, b=1/9
(2/9-1)/(10*1/5*1/9)=
-7/9/2/9=
-7/9*9/2=
-63/18=-7/2=-3.5
А)4х-3х=1 х=1. Б)-х=-13-5 х=18 в)7х+х-6х=8+2 2х=9 х=4.5
4x^2-1=0
4x^2=1 делим на 4
x^2=1/2 корень
x1=1/2
x2=-1/2