1)  х-2 1/5=5 1/20 2)10 2/7-х=2 1/2 3) х+4 2/3=6 1/4

1) х-2 1/5=5 1/20х-(2*5+1)/5=(5*20+1)/20х-11/5=101/20х=101/20+11/5х=101/20+(11*4)/(5*4)х=101/20+44/20х=145/20 сократим на 5х=29/4=7 1/42) 10 2/7-х=2  1/2х=10 2/7-2 1/2х=(10*7+2)/7-(2*2+1)/2х=72/7-5/2х=(72*2)/(7*2)-(5*7)/(2*7)х=(144/14)-(35/14)х=(144-35)/14х=109/14=7 11/143) х+4 2/3=6 1/4х=6 1/4-4 2/3х=(6*4+1)/4-(4*3+2)/3х=(25/4)-(14/3)х=(25*3)/(4*3)-(14*4)/(3*4)х=(75/12)-(56/12)х=(75-56)/12х=19/12=1  7/12