Which of the following shows the extraneous solution(s) to the logarithmic equation? log4 (x) + log4(x - 3) = log4 (-7x + 21)

a. x= -7
b. x= -3
c. x= 3 and x= -7
d. x=7 and x= -3

The correct option is C, i.e., x=3 and x=-7.

Explanation:

The given equation is,

Using product property of logarithm

On comparing both sides,

Using grouping method 4x can be written as (7x-3x). Because the product of 7 and -3 is equal to the constant term -21 and the addition of 7 and -3 is equal to the coefficient of x.

Equate each factor equal to 0.

The value of x is 3 and -7. Therefore, the option C is correct.

7 ft 6 in means 7 1/2, because 6 in is 1/2 of a foot. 7 ft 8 in means 7 2/3 because 8 in is 2/3 of a foot. 23/3 = 7 2/3. 15/2 = 7 1/2.

23/3   *   15/2   = 57 1/2

step-by-step explanation:

5/12, or 5: 12

step-by-step explanation: