Решите систему уравнений методом подстановки :
а) 3а - 2b = 12
2a-5b=19
Б) 4a+5b=6
-2a +3b=8

15(3x-2)=4(4y+3) ;5x-y=3y-2
45x-30=16y+12; 5x-4y=-2

45x-16y=42; -20x+16y=8 складываем

45x-20x=50

25x=50

x=2

5*2-4y=-2

-4y=-12

y=3

2.
а) 18
б) 35
в) 1.2
г ) 6

6) 2. It may be a dog
    3. It may be a rabbit
    4. It may be an octopus
    5. It may be a panda 
    6. It may be a butterfly
    7. It may be a duck
    8. It may be a giraffe
7) 2. Children may fly to school
    3. Aliens may visit us
    4. Trees and flowers may grow on the moon
    5. Robots may drive buses
    6. People may live to be 150
8) I may visit my friend on Friday 
    

3b-2a-4b-3a=-b-5a ........ вроде так