1/x-1/y=1/12
5x-y=18 y=5x-18
(y-x)/xy=1/12
12*(y-x)=xy
12y-12x=xy
12*(5x-18)-12x=x*(5x-18)
60x-216-12x=5x²-18x
5x²-66x+216=0 D=36 √D=6
Ответ: x₁=6 x₂=7,2.
= 12 V 12 - 12 V 75 = 12 V 2*2*3 - 12 V 5*5*3 = 12*2 V 3 - 12*5V3 = 12*(2V3 - 5 V3) =
f(x)*f'(x)<0
f(x) =x^2-4x+3