a) 1/4*4/5+1/4*6/5-4/3
=1/4(4/5+6/5)-4/3
=1/4*2-4/3
=1/2-4/3
=3/6-8/6
=-5/6
b) -7/9*13/11-(-7/9)*2/11
= -7/9*(13/11-2/11)
=-7/9*1
=-7/9
c)4/19*(-3/7)+5/7+ (-3/7)*15/19
= (-3/7)*(4/19+15/19)+5/7
=(-3/7)+1+5/7
=(-3/7)+5/7
=2/7
d)(-3/4)*5/7+(-3/4)*3/7+(-3/4)*6/7
=(-3/4)*(5/7+3/7+6/7)
=(-3/4)*2
=-3/2
e)5/9*8/15-5/9*4/15+5/-9*11/15
=5/9*(8/15-4/15-11/15)
=5/9*-7/15
=-7/27
