Answer:
answer is in explanation
Step-by-step explanation:
 
        
             
        
        
        
Answer:
Your answer will be 
y=2x-15.5
Step-by-step explanation:
Hi, there you must know the slope-intercept form which is 
y=mx+b
m=slope
b=y-intercept 
You can also use
the slope formula which is 

in this case
it will look like this
 =
= =-2
=-2
So the slope is -2 
Now we will find the y-intercept 
-7.5=2(4)+b
-7.5=8+b   Subtract 8 both sides
-15.5=b
Your y-intercept is -15.5
Hope this helps
 
        
             
        
        
        
Extra 10, 10 is half of what she ordered so she received an extra 50%
        
                    
             
        
        
        
Answer:
7
Step-by-step explanation:
 
        
             
        
        
        
If you graph out y = x^2 - 1, you'll see that it is a curved parabola. It is not a straight line. So visually this shows the equation is not linear. It's considered nonlinear.
Algebraically, the given equation does not fit the form y = mx+b which is slope intercept form. So this is more confirmation that we do not have a linear function.