Binary linear equations of 12.5 (x + y) = 9750 13 (X-Y) = 9750 process

Binary linear equations of 12.5 (x + y) = 9750 13 (X-Y) = 9750 process

From (1)
x+y=780 (3)
From (2)
x-y=750 (4)
(3) + (4) get
2x=1530
∴x=765
Substituting x = 765 into (3) yields
y=15
The solution of the system of equations is
x=765
y=15

Solving binary linear equation {x + y = 12 {30% x + 40% y = 10 * 38%

The results show that: ① x + y = 12; ① 30% x + 40% y = 10 ﹥ 8226; 38% ② from ①, y = 12-x; ③ substituting ③ into ②, 30% x + 40% (12-x) = 10 ﹥ 8226; 38% 30% x + 4.8-40% X = 3.830% - 40% x = 3.8-4.8-10% x = - 1 x = 10; ③ substituting x = 10 into ③, y = 2

Two identical triangles, with three sides of 4cm, 5cm and 6cm, form a parallelogram. What's its circumference? How many

When 4 is the common edge, perimeter = 2 × (5 + 6) = 22;
When 5 is the common edge, perimeter = 2 × (4 + 6) = 20;
When 6 is the common edge, perimeter = 2 × (4 + 5) = 18

As shown in the figure, PA is the tangent of the circle, a is the tangent point, PBC is the secant, and the bisector of ∠ APC intersects AB at point D and AC at point E

It is proved that: (1) ∵ ade = ∵ APD + ∵ pad, ∵ AED = ∵ CPE + ∵ C, ∵ APD = ∵ CPE, ∵ pad = ∵ C. ∵ ade = ∵ AED. ∵ ad = AE. (2) ∵ APB = ∵ CPA, ∵ PAB = ∵ C, ∵ APB ∽ CPA, ABAC = pbpa. ∵ ape = ∵ BPD, ∵ AED = ∵ ade = ∵ PDB, ∽ P

There is a railway station a 120m away from the river bank, and 180m away from the river bank on the other side of the river 400m downstream. For the convenience of passengers between the two stations, it is decided to build a road from a to B and drive a bridge (the bridge is perpendicular to the river bank). As the railway station and the bus station are both in the suburbs, the construction of the road between the two stations does not involve house demolition and other issues. It is known that the cost of building a road 1m is 4000 yuan, One meter bridge needs 100000 yuan. How to design the highway route to save money? At least how much money?

This kind of question ponders by oneself, even if ponders for two or three days, in this asks tells you next time you will not be able

Given that the angle AON is equal to 60 degrees, point B is the midpoint of arc AB, and point P is the first moving point on the radius on. If the radius of circle O is one, the minimum value of AP + BP is obtained

As shown in the figure:
Make CA1 so that the angle ca1n = 60 degrees
Then the triangle ACN is equal to the triangle a1cn
So AP = a1p, AP + BP = a1p + BP = A1B = Geng Hao 2

When x = 1, the value of PX3 + QX + 1 is 2003, then when x = - 1, the value of PX3 + QX + 1 is ()
A. -2001B. -2002C. -2002D. 2001

When x = 1, PX3 + QX + 1 = P + Q + 1 = 2003, so when p + q = 2002, x = - 1, PX3 + QX + 1 = - P-Q + 1 = - 2002 + 1 = - 2001

Given the fixed point a (1,0) and the moving point B on the curve C: XY + y-4 = 0, then the trajectory equation of the midpoint m of the line AB is

Let m (x, y), then the coordinates of point B be (2x-1,2y) and substituted into the curve equation: 2Y (2x-1) + 2y-4 = 0, 2xy-y + Y-2 = 0, xy = 1, and the trajectory equation is: y = 1 / X

If the polynomial x 2 + ax + B can be decomposed into (x + 1) (X-2), try to find the value of a and B

From the meaning of the question, we get x2 + ax + B = (x + 1) (X-2). And (x + 1) (X-2) = x2-x-2, so x2 + ax + B = x2-x-2. Comparing the coefficients of two sides, we get a = - 1, B = - 2

In the cube abcd-a1b1c1d1, how to prove that plane ab1d1 is parallel to plane bdc1 by vector?
In the cube abcd-a1b1c1d1, how to prove that plane ab1d1 is parallel to plane bdc1 by vector?