Is the 10 taking away 5 or was it meant to me 10.5 ?
Answer:
Hi san, A relation from a set X to a set Y is called a function if each element of X is related to exactly one element in Y. That is, given an element x in X, there is only one element in Y that x is related to. For example, consider the following sets X and Y.
This should help you a bit.
Sorry for taking so long, it wont let me type a while ago. I have it all fix now hehe. I took a picture of my work, ask me if you still don’t understand.
Answer:
10) x=9
11) x=25
Step-by-step explanation:
a triangle is 180º total
10) 2x+8x+90=180
10x=90
x=9
11) 3x+1+2x+2+2x+2=180
7x+5=180
7x=175
x=25
Step 1
<u>First situation</u>
when a ladder is leaning against a wall
Let
x-------> the distance of the bottom of the ladder from the wall
L-------> the length of the ladder
<u>Find the length of the ladder</u>
Applying the Pythagorean Theorem
------> equation 
Step 2
<u>Second situation</u>
when the ladder will be lying flat on the ground
<u>Find the length of the ladder</u>
In this situation the length of the ladder is equal to

square both sides
------> equation 
Step 3
equate equation
and equation 

therefore
<u>the answer is</u>
the length of the ladder is 
see the attached figure to better understand the problem