There are two terms since 3x is a term, and 5 is a term.
        
             
        
        
        
So to find the answer you want to isolate the y. So the first thing you want to do is to move everything to the opposite side of the = sign. You start by adding 10 to both sides. 
10+ 5y -10 = -25 +10  
 5y = -15.
the tens cancel out on the left side and on the right you get left with -15/
Since y is being multiplied by 5 you always want to do the opposite so you divide by 5.
5y/5 = -15/5
y = -3
It's hard to explain but you just have to remember that what you do to one side you must do to the other to keep the equation balanced.
        
                    
             
        
        
        
A table with columns filled with pairs of numbers that have the same ratio.
        
             
        
        
        
Answer:
x = 13
Step-by-step explanation:
This question is based on Secant Secant theorem.
Secant Secant theorem gives us the following formula:
(AB + BD)AB = (AC + CE).AC
From the above question we have the following parameters
AB = 5
BD = x
AC = 7.5
CE = 4.5
Hence,
(AB + BD)AB = (AC + CE).AC
(5 + x)5 = (7.5 + 4.5)7.5
25 + 5x = 90
Collect like terms
5x = 90 - 25
5x = 65
x = 65/5
x = 13