1)(-1,2)²-2*(-1,2)+3= 1,44-+2,4+3= 6,84

2)2а²-а-1+а²+2= 3а²-а+1

2а²-а-1-а²-2=а²-а-3

(2а²-а-1)(а²+2)= 2а³+4а²-а³-2а-а²-2= а³+3а²-2а-2

3)р²-(4-2р+2р-р²)= р²-4+2р-2р+р²= 2р²-4

4)х²+3=х²+3х-х-3

х²-х²-3х+х= -3-3

-2х=-6

х= 3