(5+1/4)·(-2+2/7)-(-4,2)÷(3+3/5)+(-6/7)·(-2+1/3)·(-3+1/4)=5,07
1)(5+1/4)·(-2+2/7)=21/4·(-12)/7=(21·(-12))/4·7=252/28=126/14=63/7=9
2)(-4,2)÷(3+3/5)=(-4+2/10)÷(18/5)=(-38)/10÷(18/5)=(-38)/10·5/8=(-38)/2·1/8=(-19)/2·1/4 =(-19)/8=(-9,5)/4=(-4,75)/2=(-2,375)
3)(-6/7)·(-2+1/3)=(-6/7)·(-5)/3=(-2/7)·(-5/1)=(-2·(-5))/7·1=10/7
4)10/7·(-3+1/4)=10/7·(-11/4)=5/7·(-11)/2=(5·(-11))/7·2=(-55)/14=(-27,5)/7= =3,92857142857
5)9-3,92857142857=9-3,92857=9-3,93=5,07