9514 1404 393
Answer:
f^-1(x) = 4+∛((x-6)/5)
Step-by-step explanation:
To find the inverse function, solve ...
x = f(y)
then write the answer in functional form.
![\displaystyle x=f(y)\\\\x=5(y-4)^3+6\\\\x-6=5(y-4)^3\\\\\frac{x-6}{5}=(y-4)^3\\\\\sqrt[3]{\frac{x-6}{5}}=y-4\\\\y=4+\sqrt[3]{\frac{x-6}{5}}\\\\\boxed{f^{-1}(x)=4+\sqrt[3]{\frac{x-6}{5}}}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20x%3Df%28y%29%5C%5C%5C%5Cx%3D5%28y-4%29%5E3%2B6%5C%5C%5C%5Cx-6%3D5%28y-4%29%5E3%5C%5C%5C%5C%5Cfrac%7Bx-6%7D%7B5%7D%3D%28y-4%29%5E3%5C%5C%5C%5C%5Csqrt%5B3%5D%7B%5Cfrac%7Bx-6%7D%7B5%7D%7D%3Dy-4%5C%5C%5C%5Cy%3D4%2B%5Csqrt%5B3%5D%7B%5Cfrac%7Bx-6%7D%7B5%7D%7D%5C%5C%5C%5C%5Cboxed%7Bf%5E%7B-1%7D%28x%29%3D4%2B%5Csqrt%5B3%5D%7B%5Cfrac%7Bx-6%7D%7B5%7D%7D%7D)
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The graph shows the function and its inverse to be reflections of each other in the line y=x, as they should be.
Answer:
x = -2
Step-by-step explanation:
since y is common in both equations, you can equate them to be equal
-2x² - 4x + 5 = 2x² + 4x + 5
4x² + 8x = 0
factor out 4x
4x(x + 2) = 0
divide both sides by 4x
x + 2 = 0
x = -2
Let the full marks be represented by = x
As given, 80% of x is 75
So,
x= 
x=93.75
Hence, full marks is 93.75
We can check also- 
=75
