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.
