Пожалуйста помогите исследовать функцию и построить ее график y=3x-x^3\9

помогите решить 

1 {3x+4y=0

  {2x+3y=1

2 {4x-3y=7

   {5x+2y=26

3 {3x-5y=0

   {8y-5x=-1 

Match the idioms with the phrases explaining them . There is one explanation you don't need.

1)A fat cat

2)while the cat is away the mice will play

3)Like a cat on hot bricks.

4)To let the cat out of the bag.

5)Like cat and dog.

A)Fighting badly

B)To tell people a secret

C)In a nervous or excited way

D)when their boss is away people often behave badly E)Very pleased about something

F)Lost your tongue

помогите решить

1 {3x+4y=0

   {2x+3y=1

2 {4x-3y=7

   {5x+2y=26 

3 {3x-5y=0

   {8y-5x=-1