Question

Please answer the number 14 & 15 ☺️

Answer 1

`a=-(29)/(60),\ b=2(1)/(3),\ c=-1(3)/(4)\\\\-(1)/(2)d=a+b+c\\\\\text{substitute}\\\\-(1)/(2)d=-(29)/(60)+2(1)/(3)+\left(-1(3)/(4)\right)\\\\-(1)/(2)d=-(29)/(60)+2(1\cdot20)/(3\cdot20)-1(3\cdot15)/(4\cdot15)\\\\-(1)/(2)d=-(29)/(60)+2(20)/(60)-1(45)/(60)\\\\-(1)/(2)d=(120+20)/(60)-\left((29)/(60)+(60+45)/(60)\right)\\\\-(1)/(2)d=(140)/(60)-(29+105)/(60)`

`-(1)/(2)d=(140)/(60)-(134)/(60)\\\\-(1)/(2)d=(6)/(60)\\\\-(1)/(2)d=(1)/(10)\ \ \ \ |\cdot(-2)\\\\d=-(1)/(5)`