Question

The area A of the rectangle shown

Answer 1

Answer:

There are generally 3 methods to solve inequalities

Step-by-step explanation:

By algebraic method

Example 1: Solve: 2x - 7 < x - 5

2x - x < 7 - 5

x < 2

By the number-line method.

Example 2. Solve  

f

(

x

)

=

x

2

+

2

x

−

3

<

0

First, solve f(x) = 0. There are 2 real roots x1 = 1, and x2 = - 3.

Replace x = 0 into f(x). We find f(0) = - 3 < 0. Therefor, the origin O is located inside the solution set.

Answer by interval: (- 3, 1)

--------------------- - 3 ++++++++ 0 ++++ 1 ----------------

3.By graphing method.

Example 2. Solve:  

f

(

x

)

=

x

2

+

2

x

−

3

<

0

.

The graph of f(x) is an upward parabola (a > 0), that intersects the x-axis at x1 = 1 and x2 = - 3. Inside the interval (-3, 1), the parabola stays below the x-axis --> f(x) < 0.

Therefor, the solution set is the open interval (-3, 1)

graph{x^2 + 2x - 3 [-10, 10, -5, 5]}