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:
$\boxed{ 2y-x=-4}$
B because pie radius square = area of a circle
Answer:
Step-by-step explanation:
if we're estimating ,we're going to round up to 8 since you can multiply that easier. 25 times 8 is 200 so estimation will be around 200
To find the tip of the bill. You will need to find how much of $86.40 is 20%. In this question, they're asking how much is the tip, not how much will the final price be.
When you multiply a percentage you move the decimal point 2 times to the left: 20. → .20
You would multiply $86.40 by .20
When you solve it 86.40 × .20 = 17.28
$17.28 is 20% of $86.40
$17.28 will be the amount he got for his tip.
