Question

What is the solution of the following quadratic inequality? x2 – 4x – 21 ≤ 0

Answer 1

Answer:

3, and -7

Step-by-step explanation:

First factor the trinomial

y=x2−4x−21

.

Find 2 numbers knowing sum (-4) and product (c = - 21). They are the numbers in the factor pair (3, -7).

y = (x + 3)(x - 7)

Solving the 2 binomials, we get:

x = -3 and x = 7

Answer 2

Answer: Its B

A number line going from negative 8 to 8. Closed circles are at negative 3 and 7. The line between the circles is shaded.