Hello from MrBillDoesMath!
Answer:
x = 10
Discussion:
A plane triangle contains 180 degrees. Adding the angles in the triangle shown in  #8 gives
(4x + 7) + (3x + 13) + 90 = 180 
Note the "right angle" shown in the triangle has been replaced by its 90 degree equivalent in the above equation.
Combining like terms gives
( 4x + 3x) + (7 + 13) + 90 = 180
7x + 20 + 90 = 180 =>                      (subtract 90 from each side)
7x + 20 + 90 - 90 = 180 - 90 = 90  =>
7x +20 = 90  =>                                (subtract 20 from each side)
7x + 20 -20 = 90 -20 =>
7x = 70 =>
x 70/7 =10.
Thank you,
MrB
 
        
             
        
        
        
Answer:
The answer is 5X+16
Step-by-step explanation:
The formula for perimeter of a triangle is a+b+c.
meaning we are adding up everything.
That is 
(x)+(x+11)+(3x+5).
collect like terms.
and u end up getting
5x+16
 
        
             
        
        
        
Answer:
The options provided do not have the correct answer. Read below.
Step-by-step explanation:
Given a 10 by 10 grid model means that there are exactly 100 individual squares present. This shows that each square is equal to 1%.
None of the options provided gives us 12% of the model.
The first option results in 50%, the second results in 5%, third option results in 0.5% and the last option results in 2%.
For 12% we can shade 12 squares completely, half of 24 squares etc.
I hope this answer helps.
 
        
             
        
        
        
Answer:
50
Step-by-step explanation:
180-105=75
180-(75+55)=50
 
        
             
        
        
        
Yes it is because -7+7=0 & 0+5=5 & 7+5=12