a) 1/2*(x+4/5)-(1/5-x) = 1/2x+1/2*4/5-1/5+x = 1/2+x +2/5-1/5 = 1 1/2x + 1/5
б) -2/3*(6/7-y) +( 2/7+y) = -2/3*6/7+2/3y+2/7+y = -(2*6)/3*7)+2/7 + 1 2/3y = -12/21+6/21+ 1 2/3y = -6/21+1 2/3y = -2/7 + 1 2/3y
в) -(y+1/8) + 3/4*(2+y) = -y-1/8+3/4*2+3/4y = -y+3/4y-1/8+3/2 = -1/4y-1/8+12/8 = -1/4y+11/8=-1/4y+1 3/8
г) 1/9*(3/5-х)- (х-1/15) = 1/9*3/5-1/9х-х+1/15 = 1/15+1/15 - 1 1/9х = 2/15-1 1/9х