Bonjours est ce que quelqu’un pourrait m’aider ?

Bonsoir,

ex_1:
x+6=8==>x=8-6==>x=2

3x=9==>x=9/3==>x=3

2x-2=2==>2x=2+2==>2x=4==>x=4/2==>x=2

4a+3=a-8==>4a-a=-8-3==>3a=-11==>a=-11/3

y+7=11==>y=11-7==>y=4

4z=7==>z=7/4

3z=2z+9==>3z-2z=9==>z=9

-5c-3=2c ==>-3=2c+5c==>7c=-3==>c=-3/7

t-5=-3==>t=-3+5==>t=2

7x=4==>x=7/4

-x-9=2x==>2x+x=-9==>3x=9==>x=9/3==>x=3

7y-3=y+3==>7y-y=3+3==>6y=6==>y=6/6==>y=1

ex_2:

1a) A=(0;3), B=(3;-1)
1b)f(0)=3 et f(3)=-1
1c) f(x)=ax+b
f(0)=a*0+b=3==>b=3
f(3)=a*3+b=-1==>3a+3=-1==>3a=-1-3==>3a=-4==>a=-4/3

f(x)=-4/3*x+3

2a) C=(0;-4) ,D=(3;2)
2b) g(0)=-4 , g(3)=2
2c)
g(x)=ax+b
g(0)=a*0+b=-4==>b=-4
g(3)=3a-4=2==>3a=6==>a=2

g(x)=2x-4

3) f(x)=g(x)
-4/3x+3=2x-4 ==>2x+4/3x=3+4==>6x/3+4x/3=7==>10x/3=7
==>x=7*3/10==>x=21/10