In the equation y^2 + ay - 24 = 0, a is a constant and y is a variable. What is the value of a ?
(1) y + 8 is a factor of y^2 + ay - 24. This implies that we can factor out y+8 from y^2 + ay - 24 = 0: (y+8)(something)=0, which means that y=-8 is one of the roots of the equation. Substitute y=-8 into y^2 + ay - 24 --> 8^2 - 8a - 24 = 0 and get the value of a. Sufficient.
(2) 3 is a root of the equation y^2 + ay - 24 = 0. The same here: substitute y=3 into y^2 + ay - 24 --> 3^2 + 3a - 24 = 0 and get the value of a. Sufficient.
Answer: D.
Hope it's clear.
(1) y + 8 is a factor of y^2 + ay - 24. This implies that we can factor out y+8 from y^2 + ay - 24 = 0: (y+8)(something)=0, which means that y=-8 is one of the roots of the equation. Substitute y=-8 into y^2 + ay - 24 --> 8^2 - 8a - 24 = 0 and get the value of a. Sufficient.
(2) 3 is a root of the equation y^2 + ay - 24 = 0. The same here: substitute y=3 into y^2 + ay - 24 --> 3^2 + 3a - 24 = 0 and get the value of a. Sufficient.
Answer: D.
Hope it's clear.