Question

For what value of x is the rational expression below undefined? 3x-12/9-x

Answer 1

Any fraction/division is undefined when the denominator/divisor = 0

Answer 2

so? what do i do

Answer 3

\(\bf \cfrac{3x-12}{{\color{red}{ 9-x}}}\qquad {\color{red}{ 9-x}}=0\implies \cfrac{3x-12}{{\color{red}{ 0}}}\)

Answer 4

so, when x = ? is the fraction undefined

Answer 5

0

Answer 6

yes, and that happens when x = ?

Answer 7

so would it be 3(x-4)

Answer 8

?

Answer 9

well.. it happens if you solve for "x" at \(\bf \cfrac{3x-12}{{\color{red}{ 9-x}}}\qquad \bbox[border: 1px solid black;padding: 5px]{ {\color{red}{ 9-x}}=0}\implies \cfrac{3x-12}{{\color{red}{ 0}}}\)

Answer 10

so.... what did you get for "x" ?

Answer 11

9-x = 0 thus x = ?