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 domain value, a, such that f(a)=1.6
f(x) = 8x +4
Given that f(a) = 1.6
We need to find the values of a.
We will substitute with x= a into the function f(x).
==> f(a) = 8a +4 = 1.6
Now we will solve for a.
==> 8a = 1.6 -4 = -2.4
Now we will divide by a.
==> a = -2.4/8 = -0.3
Then there are only one values of a that satisfies the function which is a= -0.3
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.