Question

Find the values of y which makes the expression (2y + 7) /(y2 - 2y - 15) undefined?

Answer 1

The  given expression becomes undefined when y=5 or y = -3. The answer is option D.

Step-by-step explanation:

The value of the given expression becomes undefined when the denominator equals 0.

Hence to find the value of y which makes the expression undefined, we can equate the value of the denominator to zero and solve it .

Step 1

  Equate the denominator to 0.

  y^{2}  - 2y -15 = 0

Step 2

   Solve the above equation to get the value of y.

     y^{2}  - 2y -15 = 0

    => (y-5)(y+3) =0 [ Roots of the quadratic equation]

   => y = 5 or y = -3.

Hence when y = 5 or y = -3 the denominator becomes 0, which makes the expression (2y+7)/0  and hence it is undefined.