Some one me with this problem. you. no answers, just explanation on how to solve it.

Y = 3/2 t - 5/2 ; where t = 3

Substitute t by its value. the nearness of 3/2 to t denotes multiplication.

y = (3/2 *3) - 5/2

3 is a whole number. it is 3/1 in fraction form. 
In multiplying fractions, simply multiply the numerator and the denominator.

y = (3*3 / 2*1) - 5/2
y = 9/2 - 5/2

Subtracting fractions: We can only subtract or add fractions if they all have the same common denominator. Since both fractions have 2 as denominator, we can proceed to subtracting its numerators.

y = (9-5)/2      *subtract numerators and place over the common denominator
y = 4/2            * simplify the fraction.
y = 2/1 or 2