4

Set 1: Linear Inequalities (Advanced)

Explanation

Answer: A

Solve: x24x5<0x^2 - 4x - 5 < 0 (Non-linear preview)

A.

1<x<5-1 < x < 5

✓ Correct
B.

x<1x < -1 or x>5x > 5

C.

5<x<1-5 < x < 1

D.

x<5x < -5 or x>1x > 1

Detailed Explanation

Choice A is correct. Choice A is the correct answer. Factor and test intervals. 1. Factor: (x5)(x+1)<0(x - 5)(x + 1) < 0 2. Roots: x=5,x=1x = 5, x = -1 3. Test Intervals: - x<1x < -1: Neg ×\times Neg = Pos (>0>0) - 1<x<5-1 < x < 5 (e.g., 0): Neg ×\times Pos = Neg (<0<0) - x>5x > 5: Pos ×\times Pos = Pos (>0>0) 4. Result: 1<x<5-1 < x < 5 Strategic Tip: "Less than" for a parabola opening up is the region "between" the roots. Choice B is incorrect because it describes the outside region (>0>0). Choice C is incorrect because it has wrong roots. Choice D is incorrect because it has wrong roots.

Key Steps:

The correct answer is 1<x<5-1 < x < 5

Why others are wrong:
B: Choice B is incorrect and may result from a calculation error.
C: Choice C is incorrect and may result from a calculation error.
D: Choice D is incorrect and may result from a calculation error.

🎯 Keep Practicing!

Master all sections for your best SAT score