Answer:
16
Step-by-step explanation:
To start off this problem, we are given that the line AB is equal to the line CD. In addition to that, we are given that the line EF equally intersects line AB and line CD. This provides us proof that angle AGH is equivalent to angle DHG. From this information, we can solve this problem relatively easily.
Lets work with this equation:

Next, divide 80 by 5.


This means that x is equal to 16.
You already have the answer in the question
The idea of grouping is to get the terms in groups that allow you to factor out from each group something that becomes a factor in itself, leaving two factors behind that are alike. Like this: rearrange those terms so they are in this order:
(-70y^2 - 63xy) + (90x^3 + 100yx^2). Now out of the first set we are going to factor out a -7y, and out of the second set we are going to factor out a 10x^2. When we do this, this is what we get: -7y(10y + 9x) + 10x^2(9x + 10y). As you can see, what's inside both sets of parenthesis is the same, just in a different order. We can factor that out now, leaving (9x + 10y)(10x^2 - 7y). And that is factored by grouping.
An inverse function is a function that reverses another function, so we have a function called:

Then, the inverse function will be as follows:

Given that

, we need to isolate x in terms of y:

∴

So:

and

therefore, exchanging variables x and y:

and


and

Which are the figures shown below.