Solve the inequality y2 – 3y > 18
-
A.
-3 -
B.
y 6 -
C.
y > -3 or y > 6 -
D.
y
Correct Answer: Option A
Explanation
y2 – 3y > 18 = 3y – 18 > 0
y2 – 6y + 3y – 18 > 0 = y(y – 6) + 3 (y – 6) > 0
= (y + 3) (y – 6) > 0
Case 1 (+, +) (to) (y + 3) > 0, (y – 6) > 0
= y > -3 y > 6
Case 2 (-, -) (to) (y + 3)
= y
Combining solution in case 1 and Case 2
= x
= -3