So we want to know which of the following functions has an inverse function. So an inverse function is a function that "reverses" another function. We need to put y instead of x and x instead of y. So for the first case: y=x is x=y so this function has an inverse function. y=x^2 is x=y^2 so y=sqrt(x). y=x^3 is x=y^3 so y=∛x. y=x^4 so x=y^4, y=4√x or forth root of x. So all of our functions have an inverse function.
It depends on what you are trying to calculate but the most common way I go to find percentage is to multiply by the number in decimal for ie. 50% = .5.
If you are looking for a way to do it quickly in your head I always take find out what 10% is like in the case of 100 it would be 10 so if I want to find 15% I know I can find 10% and if I cut what 10% is in half I will find 5% so likewise if I add what 10%+5% I will end up with 15%. For example, 10% of 100 is 10 half of 10 is 5 and 10+5 equals 15. If you need to find something like 20% or 30% I know that I can find 10% and instead of dividing(cutting it in half) I can multiply by 2 or 3. 10% + 10% =20%
I hope it helps, if you have more questions let me know!
Answer:
C. x = 12
Step-by-step explanation:
5(12) + 9 = 69 - 3(12) = 33
18 + 15 = 33
