<em>x</em>/<em>r</em> + <em>x</em>/<em>w</em> + <em>x</em>/<em>t</em> = 1
<em>x</em> (1/<em>r</em> + 1/<em>w</em> + 1/<em>t</em>) = 1
<em>x</em> = 1 / (1/<em>r</em> + 1/<em>w</em> + 1/<em>t</em>)
To make the solution a bit cleaner, multiply through the numerator and denominator by the LCM of each fraction's denominator, <em>rwt</em> :
<em>x</em> = 1 / (1/<em>r</em> + 1/<em>w</em> + 1/<em>t</em>) • <em>rwt</em> / <em>rwt</em>
<em>x</em> = <em>rwt</em> / (<em>rwt</em>/<em>r</em> + <em>rwt</em>/<em>w</em> + <em>rwt</em>/<em>t</em>)
<em>x</em> = <em>rwt</em> / (<em>wt</em> + <em>rt</em> + <em>rw</em>)
Answer: A
Explanation:
y = [x] - 2
Y intercept is at (0,-2) which matches the graph above
There are an infinite number of possible common denominators.
The smallest one is 12 , and every multiple of 12 is another one.
<span>f(x) = sqrt(x-5) Domain: all real numbers greater or equal to 5
f(x) = 7/(x-8) Domain: all real numbers except 8
f(x) = sqrt(x) Domain: all positive real numbers and 0
f(x) = 8x Domain: all real numbers
The domain of a function is the set of all numbers for which that function is valid. You have 4 functions and 4 possible domains to choose from. Let's work each one out.
f(x) = sqrt(x-5)
You're not allowed to take the square root of a negative number. So the domain for this function would be all values of x >= 5. That way you're taking the square root of 0 or higher. Let's see if any of your choices match that.
And you have the choice "all real number greater or equal to 5"
f(x) = 7/(x-8)
You're not allowed to divide by 0. And the denomerator becomes 0 if x equals 8. So the domain is all real numbers except 8 which happens to be one of the choices.
f(x) = sqrt(x)
This is much like the 1st choice. You can't take the square root of a negative number. So the domain is all non-negative numbers. Looking at the choices, there isn't a match, but there's the choice "all positive real numbers and 0" which means the same thing. So that's the answer.
f(x) = 8x
I don't see anything that would make it impossible to evaluate this expression. So its' domain is all real numbers. And you have that as a choice.</span>
The answer is [($109.90-$98.91)/$109.90]X100%
