Remember that a function is a rule that assigns to each element in the domain one and only one element in the range. If f(x) = 8x+4, find the...

In other words, we'll have to determine what is the x
value that whose correspondent y value, through the given expression of the function, is
1.6.

We know that f(x) = y, where the rule that assigns to
x a y value is f(x) = 8x+4.

8x + 4 =
1.6

We'll subtract 4 both sides, in order to isolate x to
the left side:

8x = 1.6 - 4

8x
= -2.4

Now, we'll divide by 8 both
sides:

x = -2.4/8

x = -0.3 or
x = -3/10

Since the value of x that makes y
to be 1.6 is denoted as a, then a = -0.3.