Respuesta :

step 1

(x - 4) • (x + 5) = 0

STEP

:

A product of several terms equals zero.

When a product of two or more terms equals zero, then at least one of the terms must be zero.

We shall now solve each term = 0 separately

Solving a Single Variable Equation:

2.2 Solve : x-4 = 0

Add 4 to both sides of the equation :

x = 4

Solving a Single Variable Equation:

2.3 Solve : x+5 = 0

Subtract 5 from both sides of the equation :

x = -5

.

Answer:

A) [tex]\huge\boxed{\sf x^2 + x - 20 = 0}[/tex]

B) [tex]\huge\boxed{\sf x = - 5 \ \ \ \ OR \ \ \ \ x = 4}[/tex]

Step-by-step explanation:

[tex]\sf (x+5)(x-4) = 0[/tex]

[tex]\rule[225]{225}{2}[/tex]

Expanding:

Expanding Brackets

[tex]\sf x^2 -4x+5x-20 = 0[/tex]

Adding / Subtracting Like terms

[tex]\sf x^2 + x - 20 = 0[/tex]

[tex]\rule[225]{225}{2}[/tex]

Solving:

Given the equation:

(x+5)(x-4) = 0

Using zero Method

Either,

x + 5 = 0   OR      x - 4 = 0

x = - 5       OR       x = 4

[tex]\rule[225]{225}{2}[/tex]