3x squared-2 (x + X squared-3) + 3 (- 2X-4 + 3x squared) And the square of 4x - 4x + 1-9x + 12x-4, where x equals - 1 4X's Square y-8xy's square + 7-4x's Square y + 12xy's square-4

3x squared-2 (x + X squared-3) + 3 (- 2X-4 + 3x squared) And the square of 4x - 4x + 1-9x + 12x-4, where x equals - 1 4X's Square y-8xy's square + 7-4x's Square y + 12xy's square-4

1、3x^2-2(x+x^2-3)+3(-2x-4+3x^2)=10x^2-8x-6；
2、4x^2-4x+1-9x^2+12x-4=(2x-1)^2-(3x-2)^2=(5x-3)(1-x)=(-5-3)(1+1)=-16；
3、4x^2y-8xy^2+7-4x^2y+12xy^2-4=4xy^2+3.

A + B = 1 the second power of a plus the second power of B = 2 for ab

a+b=1
(a+b)²=1
a²+b²+2ab=1
2ab=1-(a²+b²)=1-2=-1
ab=-1/2

The square of (a-b + C) is equal to? (fast ~)

=[(a-b)+c]²
=(a-b)²+2(a-b)c+c²
=a²-2ab+b²+2ac-2bc+c²
=a²+b²+c²-2ab+2ac-2bc

Given a (- 7,0), B (7,0), C (2, - 12), an ellipse takes C as a focus and passes through two points a and B, the trajectory equation of the other focus of the ellipse is obtained

Let another focus D (x, y)
It is defined by ellipse
AC+AD=BC+BD
AC=15,BC=13
So bd-ad = 2
So this is a hyperbola with ab as the focus
c=7,2a=2
a=1
b²=49-1=48
And bd-ad > 0, BD > ad
So it's on the left
So it's X & sup2; - Y & sup2 / 48 = 1, X

Two baskets of apples are 75 kg. Take 5 kg apples from basket a and put them into basket B. basket a is 7 kg more than basket B. how many kg of apples are there in basket a and basket B?

B now (75-7) △ 2 = 34kg
B: 34-5 = 29kg
A: 75-29 = 46 kg
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Today is the day of the month and the day of the week in English. The more detailed the better. It's better to have specific examples~

What day is it today?
Today is Thursday.
What date is it today?
Today is December 9,2010

After 4 hours, car a landed 28 kilometers behind car B. car a traveled 68 kilometers per hour, and car B how many kilometers per hour?

28 △ 4 + 68 = 7 + 68 = 75 km, a: car B travels 75 km per hour

The square of y = x + 2x-3 and X-axis intersect at point a, B and y-axis intersect at point C, find the area of triangle ABC

Let y = x & # 178; + 2x-3 = (x-1) (x + 3) = 0, then X1 = 1, X2 = - 3
So | ab | = | x1-x2 | = 4
Let x = 0, then y = - 3, that is, YC = - 3
So s △ ABC = 1 / 2 * | ab | * | YC | = 1 / 2 * 4 * 3 = 6

Car a starts from city a at 8:00 a.m. and goes to city B at 60 kilometers per hour. Car B starts from city B at 8:30 a.m. and goes to city a at 5 / 6 the speed of car A. when you get off, you can get off
How many meters is the distance between the two places?

Speed of vehicle B = 60 * (5 / 6) = 50 km / h
From 8:00 to 8:30, car a drove 60 * 1 / 2 = 30 km
5 hours from 8:30 to 1:30 p.m
AB distance between the two places
=30+（60+50）*5、
=30+110*5、
=580 km

In the polynomials A & # 178; + (2k-6) AB + B & # 178; + 9 about a and B, without AB term, we find the value of K

If there is no AB term, then (2k-6) AB = 0
As long as 2k-6 = 0, there is no AB term
Then k = 3