Question

1) n+3/20=7/12+1/9 2) 5/9+(a-2/9)=5/6

Answer 1

1)n=7/12+1/9-3/20
N=105/180+20/180-27/180
N=98/180=49/90

2)a=5/6-5/9+2/9
A=15/18-10/18+4/18
A=9/18=1/2

Answer 2

1)n+3/20=7/12+1/9
n+0,15=7/12+1/9
n+0,15=25/36
n=25/36-0,15
n=25/36-3/20
n=49/90

2)5/9+(a-2/9)=5/6
5/9+(a-2/9)=5/6
5/9+a-2/9=5/6
1/3+a=5/6
a=5/6-1/3
a=1/2