Question

What is the value of k in the function f(x)=112-kx if f(-3)=121

Answer 1

F(-3)=121=112-k(-3)

121=112+3k
minus 112 both sides
9=3k
divide by 3
k=3

Answer 2

Answer:  The required value of k is 3.

Step-by-step explanation:  We are given to find the value of k in the following function f(x) if $f(-3)=121:$

$f(x)=112-kx~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)$

Substituting x = -3 in equation (i), we get

$f(-3)=112-k\times(-3)\\\\\Rightarrow 121=112+3k\\\\\Rightarrow 3k=121-112\\\\\Rightarrow 3k=9\\\\\Rightarrow k=\dfrac{9}{3}\\\\\Rightarrow k=3.$

Thus, the required value of k is 3.