Выполните действия: 1. (7x²–5x+3)–(7x²–5)= 2. (3x+1)+(–3x²–3x+1)= 3. (a+3b)+(3a–3b)= 4. a⁴–5ab–b²–(a²+b²)= 5. (x+y–z)–(x–y)+(x–y+z)=

1. 7x²–5x+3-7x²+5=8-5x
2.3x+1-3x²-3x+1=2-3x²
3.a+3b+3a-3b=4a
4.a⁴–5ab–b²–a²-b²=a⁴–5ab–a²-2b²
5.x+y–z-x+y+x-y+z=x+y