`\text{a)} 3/5 - (3/2)^4 : (3/2)^2 + 5 13/30`
`= 3/5 - (3/2)^4 : (3/2)^2 + 163/30`
`= 3/5 - (3/2)^2 + 163/30`
`= 3/5 - 9/4 + 163/30`
`= (3/5 + 163/30) - 9/4`
`= (18 + 163)/30 - 9/4`
`= 181/30 - 9/4 = 362/60 - 135/60`
`= (362 - 135)/60 = 227/60`
`\text{b)} (1+ 2/3 - 1/4) xx (4/5-3/4)^2`
`= (3/3 + 2/3 - 1/4) xx (16/20 - 15/20)^2`
`= (5/3 - 1/4) xx (1/20)^2`
`= (20/12 - 3/12) xx 1^2/20^2`
`= 17/12 xx 1/400 = (17 xx 1)/(12 xx 400)`
`= 17/4800`
