180/(y+12)+1/6=180/y
180·6y+y(y+12)-180·6(y+12)=0, y≠0, y≠-12
1080y+y²+12y-1080y-12960=0
y²+12y-12960=0
D=144-4·(-12960)=144+51840=51984, √Д=228
у1=(-12+228)/2=108
у2=(-12-228)/2=-120
1. a) a(64-a^2)
б) х(х^2-10x+25)
2. a) a^2-ab-2b^2-4b^2-a^2=-ab-6b^2
b) 9x^2+12x+4-9x^2+6x-1=18x+3
3. (x^2+3)=(x^2-3)(x^2+3)+6(x^2+3)=x^4-9+6x^2+18=x^4+6x^2+9=(x^2+3)^2, чтд
Ответ:
1) -1+3·0= -1
2) 2-(-1)·(-3)= 2+1·(-3) = -1
3) (1+(-3))·2 = (1-3)·2 = -4
4)(3-1,2)·2= 3,6
5)(4-2)+(3-(-1)) = 2+(3+1) = 6
6) (0-(-4)) - (-2-3) = (0+4) -(-5) =4+5=9
7) 0,5-(1/2-(-1,2)) = 0,5 - (0,5+1,2) = -1,2
8) 5,2-(1,3-2,8)-2,8 = 3,9
Объяснение: