Giúp mình bài toán này với ạ

a)1/-4-4/-3+1/-3×[50%-1 3/2]

=-1/4+4/3+-1/3×[1/2-5/2]

=-1/4+4/3+-1/3×(-2)

=-1/4+(4/3+2/3)

=-1/4+2

=-1/4+8/4

=7/4

b)-1,4×15/-49-[2/5+4/3]×2 3/5

=-7/5×15/-49-[6/15+20/15]×13/5

=-7/5×-15/49-26/15×13/5

=3/7-338/75

=-2141/525

c)75%-1 1/2:0,5×5/12

=3/4-3/2:1/2×5/12

=3/4-3/2×2/1×5/12

=3/4-3/1×5/12

=3/4-5/4

=-1/2