Astrumbellum Примерно так:
1. a) (2-y)(y-8)=2y-16-y^2+8y=10y-16-y^2
б)(3c-5)^2-16c^2=9c^2-6c+25-16c^2=-7c^2-6c+25

2. а) 4x-3y=12
4x=3y+12
x=(3/4)y+3
б) 4x-3y=12
3y=4x-12
y=(4/3)x-4