3y (y is the unknown number but it represents one number only... and also 3y represents 3 multiply by y)
        
             
        
        
        
Answer:
x + y = 4 Equation 1
y = 2x -1 Equation 2
-2x + y = -1
 x + y = 4
Subtract 
You will get
- 3x = -5
Divide by -3
-3x / -3 = - 5 /-3
x = 5/3
Substitute x into equation 1
x + y = 4
x = 5/3
5/3 + y = 4
y = 4 - 5/3
y = 7/3
x = 5/3 y = 7/3
Hope this helps.
 
        
             
        
        
        
Answer:
Factor GCF: 3x(2x⁴ - 5x + 4)
Step-by-step explanation:
Simply take out the greatest variable first and then take out the GCF of the numbers to find out factored GCF.
 
        
             
        
        
        
Answer:
x = 50
Step-by-step explanation:
add all terms and set sum equal to 360
the 'hint' of (n-2)180 determines how many degrees there are inside the polygon; if 'n' equals the number of sides and the polygon has 4 sides then sum of interior angles is (4-2)180 or 2x180 which is 360
x + 10 + 3x + x + 2x = 360
combine like terms to get:  7x + 10 = 360
                                              7x = 350
                                               x = 50