Answer:
k=5
Step-by-step explanation:
We are provided with function, f ( x ) = 3 + kx − 13
which is divided by x+4 gives 15.
Here,
since f(x) is divided by x+4 so we can put :
x+4 = 0
x= -4
Putting this in f(x) -----> f(-4)
f(x) = f(-4) = 3 () + k(-4) − 13
f(-4) = 3(16) - 4k - 13
f (-4) = 48 - 4k - 13 ------------------------------------------Equation 1
Since, when f(x) is divided by x+4 , the remainder is 15 so we can say,
f(-4) = 15
putting in equation 1
f (-4) = 15 = 48 - 4k - 13
48 -4k - 13 = 15
35 - 4k = 15
35 - 15 = 4k (Moving - 4k on right hand side and 15 on the left)
or 20 = 4k
or 4k = 20
k =