3. Function Notation
Sign In
Substitute 18 for k(x).
5
To find the value of x that will make the function equal to 18, we will substitute 18 for k(x) in the given function rule. Then, we can solve for x.
k(x)= 18
LHS+12=RHS+12
Add terms
.LHS /6.=.RHS /6.
Calculate quotient
a* b/c=a/c* b
a/a=1
Identity Property of Multiplication
Rearrange equation
When x=5, the function equals 18.
When x=5, k(x)=18, so our solution is correct.