The given equation is: 
To find the line perpendicular to it, we interchange coefficients and switch the signs of one coefficient.
The equation to a line perpendicular to it is:
$ 2y-x=c$
 where, $c$ is some constant we have determine using the condition given.
It passes through $(2,-1)$ 
Put the point in our equation:
$2(-1)-(2)=c$
$c=-2-2$
$c=-4$
The final equation is:
$\boxed{ 2y-x=-4}$
 
        
             
        
        
        
Answer:
Write and solve an equation of ratios:
16 miles     20 min
-----------  = -----------
12 miles          x
Then 16x = 240, and x = 240/16 = 15.  
It will take 15 minutes to travel 12 miles.
 
        
             
        
        
        
Answer:
Number of stickers Sarah had = 28
Number of stickers she put on her binder = x.
Number of stickers left with her = 28 - x
Number of stickers Haylee had = 40
Number of stickers she put on her locker = 3x
Number of stickers left with her = 40 - 3x
Both Sarah and Haylee had the same number of stickers left.
28 - x = 40 - 3x
=> 3x - x = 40 - 28
=> 2x = 12
=> x =  = 6
Step-by-step explanation:
 
        
             
        
        
        
First  calculate after tax tire price 
$390.60 / 4 = $97.65  after tax price per tire 
take the $97.65 divided by 90 
97.65 / 90 = 1.085 
1.085 is the rate of tax he paid per tire 
        
             
        
        
        
Hi there!
PART A:
The system of equations we would use would be:
x + y = 22 (amount of items)
3x + 1y = 30 (cost)
Variables:
x = the amount of strawberry wafers bought at the price of $3
y = the amount of chocolate wafers bought at the price of $1
PART B:
To solve, we'll use substitution because we can easily isolate a variable using the first equation.
Work:
x + y = 22 (first equation)
y = 22 - x (isolating a variable)
3x + 1y = 30 (second equation)
3x + (22 - x) = 30 (substituting into the second equation)
2x + 22 = 30 (simplifying)
2x = 8 (subtracting)
x = 4 strawberry wafers
4 + y = 22 (substituting x into the first equation to solve for y)
y = 18 chocolate wafers
ANSWER:
They bought 4 strawberry wafers and 18 chocolate wafers.
Hope this helps!! :)
If there's anything else that I can help you with, please let me know!