Ответ:
1) 72; 2) 4,8; 3) - 8,8; 4) 64.
Объяснение: 5x²y³ = 8.
1) 45x²y³ = 9 × ( 5x²y³) = 9 × 8 = 72;
2) 3x²y³ = 3/5 × ( 5x²y³) = 3/5 × 8 = 24/5 = 4,8;
3) -5,5x²y³ = - 1,1 × ( 5x²y³) = - 1,1 × 8 = - 8,8 ;
4) 25x⁴y⁶ = ( 5x²y³)² = 8² = 64.
15 (3-x) -5(x +11)=1-19x
45-15х - 5х - 55= 1-19x
45-55-1=15х+5х-19х
-11=х
х=-11