If the square of X - xy-12y = 0, then the square of X - xy-2y / 2x + xy-y=

If the square of X - xy-12y = 0, then the square of X - xy-2y / 2x + xy-y=

solution
x²-xy-12y²=0
(x-4y)(x+3y)=0
When x-4y = 0, x = 4Y
The original form
=(16y²-4y²-2y²)/(32y²+4y²-y²)
=10/35
=2/7
When x + 3Y = 0, x = - 3Y
The original form
=(9y²+3y²-2y²)/(18y²-3y²-y²)
=10/14
=5/7

If the algebraic formula x ^ 4 - (A-1) x ^ 3 + (B + 3) x + 5x ^ 2-ax does not contain x ^ 3 and X terms, then a = (), B = ()

A=1
B=-2

We know that when a = 3, the value of the algebraic formula ax + B is 7; when x = - 2, the value of AX + B is - 8, then the algebraic formula is______ .

3x-2

Rational numbers a and B satisfy ab-2 + (1-B) × (1-B) = 0, try to find 1 △ AB + 1 △ a + 1] × (B + 1)... The original problem is as follows
If the rational numbers a and B satisfy ab-2 + (1-B) × (1-B) = 0, try to find the value of 1 △ (AB) + 1 × [(a + 1) × (B + 1)] + 1 × [(a + 2) × (B + 2)] +. + 1 × [(a + 2012) × (B + 2012)]

Rational numbers a and B satisfy | ab-2 | + (1-B) × (1-B) = 0
Then there must be ab-2 = 0, 1-B = 0
The solution is a = 2, B = 1
1 /ab+1/（a+1)（b+1）+1/(a+2)(b+2)+...+1/(a+2012)(b+2012）
=1/(1*2)+1/(2*3)+.+1/(2013*2014)
=1-1/2+1/2-1/3+.+1/2013-1/2014
=1-1/2014=2013/2014

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If a square is lengthened by 1 meter, its area will be increased by 11 square meters. How big is the original square?

(x+1)^2-x^2=11
x=5

When sunlight reaches the earth for about 500 seconds, how many meters is the earth from the sun

Distance = speed of light * time = 3 * 10 ^ 8m / s * 500s = 1.5 * 10 ^ 11m

Ask a physics question about sound propagation and echo
Wang Qiang and SUN Hao stood in front of the smooth wall. They were 120 meters apart and 80 meters away from the wall. When they practiced shooting, they turned their back to the wall and the target ring was 150 meters away from the wall. AFTER SUN Hao fired a shot at the target ring, they asked: (1) how long did Wang Qiang hear the sound of the gun? (2) how long did SUN Hao hear the second sound of the gun? (the propagation speed of light in the air is 340 meters per second.)

(1) How long did it take Wang Qiang to hear the gunshot: 120 △ 340 = 6 / 17 (seconds)
(2) When SUN Hao heard the second shot, it was the echo after the shot hit the ring target: (150-80) × 2 △ 340 = 7 / 17 (seconds)

Use two squares of the same size to make a rectangle. The circumference of the rectangle is 48CM. What's the area of square centimeter?

48/6=8
8*(8+8)=128

Simple: 90 plus 1 / 88 and multiplying 1 / 89
process

Divide 90 into 89 + 1, 89 times 1 / 89 to get 1, the remaining 1 plus 1 / 88 to get 89 / 88, multiply 1 / 89 to get 1 / 88! The last 1 plus 1 / 88 to get 89 / 88