5 (1+м)(1-м) -(2 - м)^2 - 8(1 - м)^2 упростить выражение

Question

5 (1+м)(1-м) -(2 - м)^2 - 8(1 - м)^2
упростить выражение

Answer 1

5(1+m)(1-m)-(2-m)²-8(1-m)²=

1) 5(1+m)(1-m)=(5+5m)(1-m)=5-5m+5m-5m²=5-5m²
2) (2-m)²=(2-m)(2-m)=4-2m-2m+m²=4-4m+m²
3) 8(1-m)²=8(1-m)(1-m)=(8-8m)(1-m)=8-8m-8m+8m²=8-16m+8m²

=(5-5m²)-(4-4m+m²)-(8-16m+8m²)=5-5m²-4+4m-m²-8+16m-8m²=
=-14m²+20m-7