Answer: x = 8
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I'm going to use the notation log(2,x) to indicate "log base 2 of x". The first number is the base while the second is the expression inside the log (aka the argument of the log)
log(2,x) + log(2,(x-6)) = 4
log(2,x*(x-6)) = 4
x*(x-6) = 2^4
x*(x-6) = 16
x^2-6x = 16
x^2-6x-16 = 0
(x-8)(x+2) = 0
x-8 = 0 or x+2 = 0
x = 8 or x = -2
Recall that the domain of log(x) is x > 0. So x = -2 is not allowed. The same applies to log(2,x) as well.
Only x = 8 is a proper solution.
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You can use the change of base rule to check your work
log base 2 of x = log(2,x) = log(x)/log(2)
log(2,(x-6)) = log(x-6)/log(2)
So,
(log(x)/log(2)) + (log(x-6)/log(2)) = 4
(log(8)/log(2)) + (log(8-6)/log(2)) = 4
(log(8)/log(2)) + (log(2)/log(2)) = 4
(log(2^3)/log(2)) + (log(2)/log(2)) = 4
(3*log(2)/log(2)) + (log(2)/log(2)) = 4
3+1 = 4
4 = 4
The answer is confirmed
Answer:
y = 2
x = 5
Step-by-step explanation:
4x + 5y = 10 | ×3 |
3x - 3y = 21 | ×4 |
12x + 15y = 30
12x - 12y = 84
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27y = -54
y = -54/27
y = 2
4x + 5y = 10 | ×3 |
3x - 3y = 21 | ×5 |
12x + 15y = 30
15x - 15y = 105
____________+
27x = 135
x = 135/27
x = 5
Answer:
2/4 and 4/8 are equivalent because you can use the butterfly method of multiplication. Meaning you multiply the numerator by the other fractions denominator and vis-versa.
Step-by-step explanation:
2 x 8 = 16
4 x 4 = 16
Answer:
The expression 5 × 2 = 10 means:
- 10 is 5 times as many as 2.
Step-by-step explanation:
Given the expression
From the expression, it is clear that we can determine that when we multiply 2 by 5 to get 10.
In other words, we can determine the value 10 by:
It means 10 is 5 times as many as 2.
Therefore, the expression 5 × 2 = 10 means:
- 10 is 5 times as many as 2.
