JAMB 1993 · UME · Q20

Solve the inequality y2−3y>18y^2 - 3y > 18.

Worked solution (try it first)
  1. Bring everything to one side: y2−3y−18>0y^2 - 3y - 18 > 0.
  2. Factorise: (y−6)(y+3)>0(y - 6)(y + 3) > 0, so the roots are y=6y = 6 and y=−3y = -3.
  3. The graph of a positive y2y^2 quadratic is a U shape, so it is above zero outside the roots: y<−3y < -3 or y>6y > 6, option B.

Report a problem with this question