Find and [t ex]a_i[/tex] if for every positive integer i,
a) = {−i,−i+−1,0,−1,i}.
b) = −i, i.
c) = [−i, i], that is, the set of real numbers x with −i ≤ x ≤ i.
d) = [i,[infinity]], that is, the set of real numbers x with x ≥ i.

the 4th choice is the correct one

step-by-step explanation:

step-by-step explanation:

step 1: solve one of the equations for one of the variables. let's solve the first equation for y:

step 2: substitute that equation into the other equation, and solve for x.

step 3: substitute x = 4 x = 4 x=4 into one of the original equations, and solve for y.