Step-by-step explanation:
Since this is a rectangle these two equations for the length have to equal each other.
2x+4=7x-1
We now need to get all of the x's on one side and constant numbers on the other side.
add 1 to both sides and subtract 2x from both sides.
5=5x
divide 5 from both sides.
x=1
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
Distance divided by time is speed. To find the rate of speed, divide 40 yards by 4.24 seconds which is approximately 9.43 yards per second. 9.43 yards per second is the rate of speed.
She'll have 17 with a remainder, just divide 139 by 8.
1. - 3, +4 2. +2, - 5 3. +9, +1
