Answer:
90 feet
Step-by-step explanation:
30x3=90
Answer:
i would say (B) or (C) but ill go with (C)
Step-by-step explanation:
![\bf f(x)=(x-6)e^{-3x}\\\\ -----------------------------\\\\ \cfrac{dy}{dx}=1\cdot e^{-3x}+(x-6)-3e^{-3x}\implies \cfrac{dy}{dx}=e^{-3x}[1-3(x-6)] \\\\\\ \cfrac{dy}{dx}=e^{-3x}(19-3x)\implies \cfrac{dy}{dx}=\cfrac{19-3x}{e^{3x}}](https://tex.z-dn.net/?f=%5Cbf%20f%28x%29%3D%28x-6%29e%5E%7B-3x%7D%5C%5C%5C%5C%0A-----------------------------%5C%5C%5C%5C%0A%5Ccfrac%7Bdy%7D%7Bdx%7D%3D1%5Ccdot%20e%5E%7B-3x%7D%2B%28x-6%29-3e%5E%7B-3x%7D%5Cimplies%20%5Ccfrac%7Bdy%7D%7Bdx%7D%3De%5E%7B-3x%7D%5B1-3%28x-6%29%5D%0A%5C%5C%5C%5C%5C%5C%0A%5Ccfrac%7Bdy%7D%7Bdx%7D%3De%5E%7B-3x%7D%2819-3x%29%5Cimplies%20%5Ccfrac%7Bdy%7D%7Bdx%7D%3D%5Ccfrac%7B19-3x%7D%7Be%5E%7B3x%7D%7D)
set the derivative to 0, solve for "x" to get any critical points
keep in mind, setting the denominator to 0, also gives us critical points, however, in this case, the denominator will never be 0, so... no critical points from there
there's only 1 critical point anyway, and do a first-derivative test on it, check a number before it and after it, to see what sign the derivative has, and thus, whether the graph is going up or down, to check for any extrema
2x + 4(x - 1) = 2 + 4x
2x + 4x - 4 = 2 + 4x
6x - 4 = 2 + 4x
6x - 4x = 2 + 4
2x = 6
x = 3........there is 1 solution
25 - x = 15 - (3x + 10)
25 - x = 15 - 3x - 10
25 - x = -3x + 5
3x - x = 5 - 25
2x = - 20
x = -20/2
x = -10.....there is 1 solution
4x = 2x + 2x + 5(x - x)
4x = 4x + 5x - 5x
4x = 4x......this has infinite solutions
learn this...
if ur equation ends in a variable equaling a number, then there is one solution.
if ur equation ends in something not equal, like 2 = 4, or 4 = 6, then there is 0 solutions.
if ur equation ends in something equal to something,(the same) like 2 = 2, or 4x = 4x, then there is infinite solutions
