1)
а²b²*(a²+3ab-b²)=
= a⁴b²+3a³b³-a²b⁴
-m(m-2) +5m²(1-3m)=
=-m²+2m+5m²-15m³=
=4m²+2m-15m³
2)
6(5x-4)-3(3x-2)=5
30x-24-(9x-6)=5
30x-24-9x+6=5
30x-9x=5+24-6
21x= 23
x=23/21
x= 1 2/21
Проверим:
6(5 * 23/21 -4)- 3(3* 23/21 -2)=5
6 ( 115/21 - 84/21 ) - 3( 23/7 - 14/7 )=5
6 * ( 31/21) - 3 * (9/7) =5
62/7 - 27/7 =5
35/7=5
5=5