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:
10
Step-by-step explanation:
j=6
k=4
Rewrite the equation. So let's do that-
2.5(6*4)/6
6 and the other 6 cancel out so we are left with 2.5*4
Which is then equal to 10.
By the way, whenever you see the same number in a division problem on the numerator and denominator, just cancel them out because if you still did 2.5(6*4)/6, you would still get 10. I was just simplifying it!
I'm going to assume you meant crayon instead of can:
First step is to find how many boxes she/he has left.
30 - 10 = 20
So the teacher has 20 boxes left;
Now, knowing that each box has 16 crayons, then we simply multiply the 20 by 16 to find the total number of crayons left over:
20 x 16 = 320
So the art teacher has 320 crayons left over.
Hope this helps!