Answer:
The x-coordinate is \dfrac{\pi}{6}[/tex].
Step-by-step explanation:
We are given a function f(x) as:

Now on differentiating both side with respect to x we get that:

When 
this means that 
Hence, cosine function takes the negative value in second and third quadrant but we have to only find the value in the interval
.
also we know that
----(1) (which lie in the second quadrant)
so on comparing our equation with equation (1) we obtain:

Hence, the x-coordinates where
for
is
.
(3x+2) (x-7)
FOIL
first 3x*x = 3x^2
outer 3x*-7 = -21x
inner = 2*x = 2x
last 2*-7 = -14
add them together = 3x^2 -21x+2x -14
combine like terms 3x^2 -19x -14
The ratio would be 8:20 or 8 to 20
Let x be the unknown number
x×55%=121
x=121÷55%
x=220
So 121 is 55% of 220
Answer:

Step-by-step explanation:
![\sf 2x + 4(7-x) \\\\Resolving \ Parenthesis\\\\2x + 28-4x \\\\Combining\ like\ terms\\\\2x-4x +28\\\\-2x + 28\\\\\rule[225]{225}{2}](https://tex.z-dn.net/?f=%5Csf%202x%20%2B%204%287-x%29%20%20%5C%5C%5C%5CResolving%20%5C%20Parenthesis%5C%5C%5C%5C2x%20%2B%2028-4x%20%5C%5C%5C%5CCombining%5C%20like%5C%20terms%5C%5C%5C%5C2x-4x%20%2B28%5C%5C%5C%5C-2x%20%2B%2028%5C%5C%5C%5C%5Crule%5B225%5D%7B225%7D%7B2%7D)
![\sf \\12x-(4+2x)\\\\12x-4-2x\\\\Combining \ like \ terms\\\\12x-2x - 4\\\\10x-4 \\\\\rule[22]{225}{2} \\2(10-x)+3(12-x) \\\\Resolving \ Parenthesis\\\\20-2x + 36 -3x\\\\Combining \ like \ terms\\\\20+36 -2x-3x\\\\56 - 5x \\\\\rule[225]{225}{2}](https://tex.z-dn.net/?f=%5Csf%20%5C%5C12x-%284%2B2x%29%5C%5C%5C%5C12x-4-2x%5C%5C%5C%5CCombining%20%5C%20like%20%5C%20terms%5C%5C%5C%5C12x-2x%20-%204%5C%5C%5C%5C10x-4%20%5C%5C%5C%5C%5Crule%5B22%5D%7B225%7D%7B2%7D%20%5C%5C2%2810-x%29%2B3%2812-x%29%20%5C%5C%5C%5CResolving%20%5C%20Parenthesis%5C%5C%5C%5C20-2x%20%2B%2036%20-3x%5C%5C%5C%5CCombining%20%5C%20like%20%5C%20terms%5C%5C%5C%5C20%2B36%20-2x-3x%5C%5C%5C%5C56%20-%205x%20%5C%5C%5C%5C%5Crule%5B225%5D%7B225%7D%7B2%7D)
![\sf 7(x-1)-6(x+1)\\\\Resolving \ Parethesis\\\\7x-7-6x-6\\\\Combining \ like \ terms\\\\7x-6x-7-6\\\\x - 13\\\\\rule[225]{225}{2}](https://tex.z-dn.net/?f=%5Csf%207%28x-1%29-6%28x%2B1%29%5C%5C%5C%5CResolving%20%5C%20Parethesis%5C%5C%5C%5C7x-7-6x-6%5C%5C%5C%5CCombining%20%5C%20like%20%5C%20terms%5C%5C%5C%5C7x-6x-7-6%5C%5C%5C%5Cx%20-%2013%5C%5C%5C%5C%5Crule%5B225%5D%7B225%7D%7B2%7D)
Hope this helped!
~AnonymousHelper1807