1) = y²+8y+16 -100+y² = 2y² +8y - 84
2) 3x(3x²-7x+2) -x(9x² -12x +4) = 1 - 9x²
9x³ -21x² + 6x - 9x³ + 12x² - 4x = 1 - 9x²
- 9x² +2x = 1 - 9x²
2x =1
x=1/2
3) (1 -h²)(h²+1) - 4h(6h² -5h -21) - 6h² + 10h =
= 1-h^4 - 24h³ +20h² +84h -6h² + 10h =
= - h^4 - 24h³ +14h² +94h +1