First join the log4 on the left:
log4( x*(x-3) = log4(-7x+21)
Then x = -7, works: -7*(-10)=70 = -7*(-7)+21
x=-3, 18 = 42, does not work
x=3 0=0 works,
However, when one puts x = -7 in the *original* exression, log4(-7) or log4(-10) do not exist (you know why?). So x= -7 is extraneous.
Now x=3 gives log4(0) on the left and right, which does not exist.
So, C is the answer, both are extraneous. Seem to work but indeed don't work in the *original* equation
This is the number of combinations of 2 from 23
23C2 = 23! / 2! 21!
A quick way to do this is 23*22 / 2 = 253
The algebraic expression of "Four more than the quotient of a number and 3 is 9" is 
The value of x=15
Step-by-step explanation:
We need to express "Four more than the quotient of a number and 3 is 9" as algebraic expression.
Let the number = x
Solving:
quotient of a number and 3: 
Four more than the quotient of a number and 3: 
Four more than the quotient of a number and 3 is 9: 
Now, finding value of x:

So, value of x = 15
Keywords: Algebraic expression
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Answer:
Answer is 75cm squared.
Step-by-step explanation:
10x15 = 150
divide by 2
final answer is 75.