Question

Solve this equation using an algebraic method: (x + 4)( x - 4) = 9

Answer 1

(x+4) (x-4) = 9
x^2 -4x+4x -16 = 9
x^2 -16 = 9
x^2 = 9+16
x = √25
x = +5 & -5

Answer 2

Answer:

The value of x is +5 and -5

Step-by-step explanation:

Step 1:  

Given Data:

(x + 4)( x - 4) = 9  

To Find:

Solve the Equation using an Algebraic Method

Step 2:

Therefore, (x+4)(x-4)can be written as

x2 - 42=9    

a2-b2 = (a + b) (a-b)

Step 3:

(x+4) (x - 4) = 9

x2 - 4x+4x -16 = 9

Step 4:

x2 -16 = 9(Bring 16 to RHS so the sign changed to ‘+’)

x2 = 9+16

x2=25

x = √25

x = +5 and  -5