The slopes of perpendicular lines are negative reciprocals.The slope of the given line is 4.The slope of the perpendicular is -1/4.
Now we need to find the equation of a line that has slope -1/4 and passes through the point (4, 20).
We use the point-slope form of the equation of a line, where m = slope, and the point is (x1, y1).
y - y1 = m(x - x1)
y - 20 = -1/4(x - 4)
-4y + 80 = x - 4
x + 4y = 84
Answer:
A salad costs $2.50
A sandwich costs $4.50
A drink costs $1.25
Step-by-step explanation:
Let x represent the salad, y represent the sandwich, and z represent the drink.
Since three salads, two sandwiches, and one drink cost $17.75:
3x + 2y + z = 17.75 (1)
Since one salad, one sandwich, and three drinks cost $10.75:
x + y + 3z = 10.75 (2)
Since a salad costs twice as much as a drink:
x = 2z (3)
Multiply the equation 2 by -2 then, sum the equation 1 and equation 2:
-2x - 2y - 6z = -21.50
3x + 2y + z = 17.75
→ x - 5z = -3.75
Replace the x with 2z using equation 3:
2z - 5z = -3.75
-3z = -3.75
z = 1.25
x = 2z → x = 2.50
x + y + 3z = 10.75 → 2.50 + y + 3.75 = 10.75 → y + 6.25 = 10.75 → y = 4.50
Answer:
P43=4!(4–3)!=241=24
Step-by-step explanation:
There are four choices you can make for the lead reindeer. For each possible choice, there are then three remaining you can choose to fly second, making 4×3=12 choices for the lead pair. For each possible choice there are two remaining reindeer to take up the back position, making 12×2=24 choices for the team of three.
This type of problem is called a permutation problem, and we write Pnr for the number of ways of choosing r items from n possibilities when the order of the items matters. In this case we are choosing 3 reindeer from 4 possibilities, and the order they appear in the flying line does matter, so the answer we want is P43. The general formula is Pnr=n!(n−r)!. For the answer we are looking for we therefore have:
P43=4!(4–3)!=241=24
Y = 2x/x-7
x = 2y/y-7
xy - 7x = 2y
-7x = 2y - xy
-7x = y(2-x)
y = -7x / 2-x
y = 7x / x-2
f-¹(x) = 7x / x-2
