Question

Помогите пожалуйста

Answer 1

1) 5х²-10х+9-2х²+14х-20

3х²+4х-11

2) -m^5+2m^4-6m^5+12m³-18m³

${ - 7m}^{5}+{2m}^{4} - {6m}^{3}$

3) 0.2a³+1.4a²-2.2-0.9a³+1.8a²+3

-0.7a³+3.2a²+0.8

4) 6x²y-xy²-8x²y+2xy²-xy+7

-2x²y+xy²-xy+7