1) x=4/9+2/5
x=(4*5)/40+(2*9)/40
x=20/40+18/40
X=38/40
x=19/20
2) x=1/12-7/24
x=(1*2)/24-7/24
x=(2-7)/24
x=-5/24
Х- 2/5=4/9
Х=4/9+2/5
Х=38/45
7/24+х=1/12
Х=7/24 -1/12
Х=5/24
1) x=4/9+2/5
x=(4*5)/40+(2*9)/40
x=20/40+18/40
X=38/40
x=19/20
2) x=1/12-7/24
x=(1*2)/24-7/24
x=(2-7)/24
x=-5/24
Х- 2/5=4/9
Х=4/9+2/5
Х=38/45
7/24+х=1/12
Х=7/24 -1/12
Х=5/24