The width is 3m because 3*7 is 21m^2. Also they said the length is 4 more than the width (3+4=7)
        
             
        
        
        
I hope this helps you 
A) x=6 y=3 3=6-4 3=2 false
B) x=4 y=0 0=4-4 0=0 true
C) x=3 y=-1 -1=3-4 -1=-1 true 
D) x=2 y =-4 -4=2-4 -4=-2 false
 
        
                    
             
        
        
        
Answer:
a) x = -1.5
b) x = 1
Step-by-step explanation:
For problem a, you can start by subtracting 3x from both sides to gather all the like terms together:
7x + 5 = 3x - 1
-3x         -3x
4x + 5 = -1
Next, to get the coefficients on one side, you subtract 5 from both sides:
4x + 5 =  -1
     -5      -5
4x = -6
Now, you divide by 4 on both sides to isolate x:
x = -6/4 = -1.5 --- > x = -1.5
For problem b, you start by subtracting 3x from both sides(kinda like problem a):
5x + 12 = 3x + 14
-3x          -3x
2x + 12 = 14
Next, you can subtract 12 from both sides, isolating the "x term".
2x + 12 = 14
        -12  -12
2x = 2
Lastly, you can divide by 2 to get x:
x = 1
 
        
                    
             
        
        
        
Answer:
Step-by-step explanation:
- −3 2/3 = x − 1 1/4
- x = - 3 2/3 + 1 1/4
- x = - 2 - 2/3 + 1/4
- x = - 2 - 8/12 + 3/12
- x = - 2 - 5/12
- x = - 2 5/12