![f(x)=5x^2-5x-6 \\ \quad \\ \begin{cases} f(\boxed{x+h})=5(\boxed{x+h})^2-5(\boxed{x+h})-6 \end{cases}\qquad thus \\ \quad \\ \cfrac{f(x+h)-f(x)}{h}\qquad \textit{will be then} \\ \quad \\ \cfrac{[5({x+h})^2-5({x+h})-6]\quad -\quad [5x^2-5x-6]}{h} \\ \quad \\ \cfrac{[5(x^2+2xh+h^2)-5(x+h)-6]-[5x^2-5x-6]}{h} ](https://tex.z-dn.net/?f=f%28x%29%3D5x%5E2-5x-6%0A%5C%5C%20%5Cquad%20%5C%5C%0A%0A%5Cbegin%7Bcases%7D%0Af%28%5Cboxed%7Bx%2Bh%7D%29%3D5%28%5Cboxed%7Bx%2Bh%7D%29%5E2-5%28%5Cboxed%7Bx%2Bh%7D%29-6%0A%5Cend%7Bcases%7D%5Cqquad%20thus%0A%5C%5C%20%5Cquad%20%5C%5C%0A%5Ccfrac%7Bf%28x%2Bh%29-f%28x%29%7D%7Bh%7D%5Cqquad%20%5Ctextit%7Bwill%20be%20then%7D%0A%5C%5C%20%5Cquad%20%5C%5C%0A%5Ccfrac%7B%5B5%28%7Bx%2Bh%7D%29%5E2-5%28%7Bx%2Bh%7D%29-6%5D%5Cquad%20-%5Cquad%20%5B5x%5E2-5x-6%5D%7D%7Bh%7D%0A%5C%5C%20%5Cquad%20%5C%5C%0A%5Ccfrac%7B%5B5%28x%5E2%2B2xh%2Bh%5E2%29-5%28x%2Bh%29-6%5D-%5B5x%5E2-5x-6%5D%7D%7Bh%7D%0A)

and surely, you'd know what that is
7x+12+63=180
8x+12=180
Subtract 12 from both sides
8x= 168
=c=21
10x-40=50
Add 40 to both sides
10x=90
X=9
4x+72+2x-12=180
6x +60 =180
Subtract 60 from both sides
6x=120
X=20
Vsphere=(4/3)pir^3
when we replace r with 2r
newvsphere=(4/3)pi(2r)^3
newvsphere=(4/3)pi8r^3
newvsphere=8((4/3)pir^3)
newvsphere=8(vsphere)
it's volume is multipliied by 8
that is choice C, because 2^3=8, it's vollume is 8 times original voluem
answer is C
Step-by-step explanation:
a) The total cost C is given by

b) If the total cost is $400, then we can solve for the number of hours as

Solving for n, we get

Answer:
I think B
Step-by-step explanation: