If the square of X + 2 y square - 2XY + 8y + 16 = 0, then X-Y is equal to

If the square of X + 2 y square - 2XY + 8y + 16 = 0, then X-Y is equal to

X squared + 2 y squared - 2XY + 8y + 16 = 0
x²-2xy+y²+y²+8y+16=0
(x-y)²+(y+4)²=0
∴x-y=0,y+4=0
∴x=y
∴x-y=0

What is the maximum distance between the point on the circle x * x + y * y = 16 and the line X-Y = 3
What is the maximum distance between the point on the circle x * x + y * y = 16 and the line X-Y = 3? What is the equation of the circle with the point (2, - 1) as the center and tangent to the line x + y = 6?

1. The distance from O origin to X-Y = 3 is 3 / 2 * root 2,
Add a radius to the distance from the center of the circle to the straight line, and subtract a radius if it is the smallest
The distance is = 3 / √ 2 + 4 = 3 √ 2 / 2 + 4
2. Calculate the radius of circle r = 5 √ 2 / 2, R & sup2; = 25 / 2 by the distance from point to line
So the equation is (X-2) & sup2; + (y + 1) & sup2; = 25 / 2

The maximum distance between the point on the circle x ^ 2 + y ^ 2-2y = 3 and the line x-y-5 = 0 is ()
Option A.3 √ 2 + 1 B.3 √ 2 + 2 C.3 √ 2-2 D.3 √ 2-1

The center of the circle is (0,1) and the radius is 2
Distance from center of circle to straight line: 3 √ 2
So the longest distance is: 3 √ 2 + 2
Choose B

Let the ellipse C: x ^ 2 / A ^ 2 + y ^ 2 / b ^ 2 = 1 pass through the fixed point (1,2), then the minimum distance between the center of the ellipse and the guide line

For children's shoes on the first floor, the formula of ellipse is x = a ^ 2 / C
Attention, it's the center, not the focus!
The final answer should be 2 + √ 5

Synchronous analysis and evaluation of fifth grade volume I answer to question 5 on page 25 of Mathematics
Bruce Lee paid 45.6 yuan for 1 kg of candy and 3 kg of biscuits. Xiao Li bought the same biscuit and candy, each one kilogram, and paid 21.6 yuan. How much are candy and biscuit?

Candy 9.6 yuan / kg, biscuit 12 yuan / kg!

Given circle C1: x ^ 2 + y ^ 2 + 2x + 6x + 6 = 0. Circle C2: x ^ 2 + y ^ 2-4x-8y + 7 = 0, find the center distance between two circles

Circle C1: x ^ 2 + y ^ 2 + 2x + 6x + 6 = 0
Did you type the XY letter wrong? Anyway, it's OK to find out the center of the circle. The center of the circle is (x first term coefficient divided by - 2, y first term coefficient divided by - 2)
. circle C2: x ^ 2 + y ^ 2-4x-8y + 7 = 0
Then (X-2) ^ 2 + (y-4) ^ 2 = 13
The center of the circle is (2,4)
Because the data is not right, so you can do it yourself

Happy oral math
1. The speed of a car is 90 kilometers per hour, what can be written? 2. The speed of Xiaodou walking is 65 kilometers per minute, what can be written? 3. The speed of soldiers typing is 65 kilometers per minute, what can be written? 4. The speed of a train is 100 km / h, what does it mean? 5. The speed of an aircraft is 900 km / h, what does it mean?

How to write math essay in Grade Four

A square with a side length of B decimeters can increase its area by () square decimeters when the side length is increased by 10%?

A square with a side length of B decimeters can increase its area by (0.21b) square decimeters by 10%
B(1+10%)²=121%B

When a simple harmonic moving object passes through point a, the acceleration is 2m / S ^ 2, pointing to point B; when it passes through point B, the acceleration is 3
If the distance between AB and ab is 10 cm, please determine its equilibrium position

Acceleration and interior direction system, the equilibrium position is between ab,
Let the equilibrium position be o, OA = x1, OB = x2,
A position, kx1 = MA1,
B position, kx2 = ma2,
So X1 / x2 = A1 / A2 = 2 / 3,
x1+x2=10cm,
So X1 = 4cm

There is a rectangular sheet of iron 40 cm in length and 30 cm in width. Cut out an equal small square at its four corners to make a cuboid uncovered sheet iron box 5 cm in depth (the thickness of welding joint is not included). What is the volume of the box?

40-5 × 2 = 30 (CM) 30-5 × 2 = 20 (CM) 30 × 20 × 5 = 3000 (cm3) a: the volume of the tin box is 3000 cubic centimeters