If (y - 1)(z - 9) +15(z - 9) = 0, then which of the following must be true? Choices
A) y = -4 and z = -3 B) y = -4 or z = -3 C) y = -4 or z = 9 D) y = 1 and z = 3 E) y = 1 or z = 3
factor out:   (z-9)(y-1+15)=0   (z-9) (y+14) = 0   So by checking options we get ,   y = -4 or z = 9.
<result>C</result>
If (y - 1)(z - 9) +15(z - 9) = 0, then which of the following must be true?