What does r equal in 4r+5=3r
1 answer:
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Answer:
The value of x = 11 and y = 2
Step-by-step explanation:
Given : parallelogram LMNO, MP = 21 m, LP = (y + 3) m, NP = (3y – 1) m, and OP = (2x – 1) m.
We have to find values of x and y.
Let P be the point of intersection of diagonals OM and LN.
In a parallelogram diagonal bisects at right angles and point of intersection divide diagonal in equal parts.
Thus, OP = MP and LP = PN
OP = MP , substitute the values, we get,
(2x-1) = 21
⇒ 2x = 22
⇒ x = 11
LP = PN , substitute the values, we get,
y + 3 = 3y -1
⇒ 3y - y = 4
⇒ 2y = 4
⇒ y = 2
Thus, the value of x = 11 and y = 2
Answer:
P is exactly 3km east from the oil refinery.
Step-by-step explanation:
Let's d be the distance in km from the oil refinery to point P. So the horizontal distance from P to the storage is 3 - d and the vertical distance is 2. Hence the diagonal distance is:
So the cost of laying pipe under water with this distance is
And the cost of laying pipe over land from the refinery to point P is 400000d. Hence the total cost:
We can find the minimum value of this by taking the 1st derivative and set it to 0
We can move the first term over to the right hand side and divide both sides by 400000
From here we can square up both sides
d = 3
So the cost of pipeline is minimum when P is exactly 3km east from the oil refinery.