Solve the problem.
-If $f ( x ) = \frac { x - B } { x - A } , f ( 4 ) = 0$, and $f ( 9 )$ is undefined, what are the values of $A$ and $B$ ?
A) $\mathrm { A } = - 4 , \mathrm {~B} = - 9$
B) $\mathrm { A } = 9 , \mathrm {~B} = 4$
C) $\mathrm { A } = 4 , \mathrm {~B} = 9$
D) $A = - 9 , B = - 4$

Question

Quizplus · Accepted Answer

For $f(4) = 0$, the numerator must be 0 when $x = 4$, so $B = 4$. For $f(9)$ to be undefined, the denominator must be 0 when $x = 9$, so $A = 9$.

Solve the Problem f(x)=x−Bx−A,f(4)=0f ( x ) = \frac { x - B } { x - A } , f ( 4 ) = 0f(x)=x−Ax−B​,f(4)=0

Solve the Problem $f ( x ) = \frac { x - B } { x - A } , f ( 4 ) = 0$