6. n=4/3-4/3×[4/3-(0,(3))²]:4 8/9
n=4/3-4/3×[4/3-(3/9)²]:44/9
n=4/3-4/3×[4/3-(1/3)²]:44/9
n=4/3-4/3×(4/3-1/9):44/9
n=4/3-4/3×(12/9-1/9):44/9
n=4/3-4/3×11/9:44/9
n=4/3-44/27:44/9
n=4/3-44/27×9/44
n=4/3-1/3
n=3/3
n=1∈N
9. a= -2-(-4)
a= -2+4
a=2
b= -3+(-3)²-(-2)×(-4)
b= -3+9-8
b=6-8
b= -2
(a-3×b)/(3×a+b)=[2-3×(-2)]/[3×2+(-2)]=[2-(-6)]/[6+(-2)]=(2+6)/(6-2)=8/4=2