Question

Find all values of k such that the graph of the inequality (x-2)(x-5)(x-k) >= 0 consists of a single interval on the number line.

Answer 1

(x - 2)(x - 5)(x - k) >= 0

Let's set each term equal to 0

x - 2= 0

Add 2 to both sides

x = 2.

x - 5 = 0

Add 5 to both sides

x = 5

x - k = 0

Add k to both sides

x = k

Since x = 2 and 5, k = 2, 5

Let's plug our numbers into the inequality.

(2 - 2)(2 - 5)(2 - 2) >= 0

(0)(-3)(0) >= 0

0>=0

(5 - 2)(5 - 5)(5 - 5) >= 0

(3)(0)(0) >= 0

0 >= 0

This proves that 2 and 5 are equal to k