Answer:
b = 10
Step-by-step explanation:
The area (A) of a triangle is calculated as
A =  bh ( b is the base and h the height )
 bh ( b is the base and h the height )
Here h = 3x + 15 and A = 15x + 75, thus
 × b × (3x + 15) = 15x + 75
 × b × (3x + 15) = 15x + 75
Multiply both sides by 2 to clear the fraction
b(3x + 15) = 30x + 150
Divide both sides by (3x + 15)
b =  ← factor numerator and denominator
 ← factor numerator and denominator
   =  ← cancel the factor (x + 5) on numerator/denominator
 ← cancel the factor (x + 5) on numerator/denominator
   = 
   = 10
 
 
        
                    
             
        
        
        
x   =   9
Since M is the midpoint of XY:
XM   =   MY
XM =  2x  +  11
MY  =  5x  -  16
2x  +  11   =  5x  -  16
5x  -  2x   =  11  +  16
3x    =   27
x    =  27/3
x   =   8
Learn more here: brainly.com/question/18315903
 
        
             
        
        
        
Answer:
P = t - f
Step-by-step explanation:
First we need to find how many pages in total she needs so 1,000/80 - 12.5 so 13 pages. Then 380/80 4.75 of a page filled so subtract that from 12.5 to get 8 pages left to fill. 
let p = pages left to fill 
let T = total pages needed
let F = pages already filled