1/2+1/2*(x-1)= 7/2
1/2-x/2-1/2=7/2
-x/2=7/2
x= -7
5/12 : (1/3-3/4)-5/3 *6/5= 5/12 : (4/12- 9/12)- 2=5/12* (-12/5 ) -2= -1 -2= -3
√(225/16)+ (3√ 3/ 5- 3√5 / 10) * √5/3= 15/4 + (6√3/ 10 - 3√5 / 10) * √5/3=
15/4 + (6√3/ 10 - 3√5 / 10) * √5/3= 15/4+ 3√5/ 10* √5 / 3=15/4 + 5/10=
=15/4 - √15/10