Given X & sup2; + xy = 3, XY + Y & sup2; = - 2, find the value of X & sup2; - Y & sup2;? X & sup2; + 4xy + 3Y & sup2;? 2x & sup2; - xy-3y

Given X & sup2; + xy = 3, XY + Y & sup2; = - 2, find the value of X & sup2; - Y & sup2;? X & sup2; + 4xy + 3Y & sup2;? 2x & sup2; - xy-3y

X & sup2; + xy = 3, XY + Y & sup2; = - 2 minus X & sup2; + xy-xy-y & sup2; = 3 + 2x & sup2; - Y & sup2; = 5x & sup2; + xy = 3 (1) XY + Y & sup2; = - 2 (2) (2) * 3 + (1) x & sup2; + XY + 3xy + 3Y & sup2; = 3-6x & sup2; + 4xy + 3Y & sup2; = - 3 (1) * 2 - (2) * 32x & sup2; + 2xy-3xy-3y & sup2

How much is (2x / 2-3y) + XY - (5xy / XY)

(2x/2-3y)+xy-(5xy/xy)=x-3y+xy-5

(1) 4 / 5 × 1 / 4-2 / 20 x = 1 / 20 (2) 17-120% x = 5 (3) x-20% x = 40 (with process)

(1)
4 of 5 × 1 of 4-2 x = 1 of 20
1/5-x/2=1/20
Multiply both sides of the equation by 20 at the same time
4-10x=1
The result of the transfer is as follows:
10x=4-1
10x=3
x=3/10
(2)
17-120%x=5
The result of the transfer is as follows:
1.2x=17-5
1.2x=12
x=10
(3)
x-20%x=40
x-0.2x=40
0.8x=40
x=40/0.8
x=50

Let AX = B have unique solution and a be mxn matrix
Let AX = B have a unique solution and a be an mxn matrix, then there must be rank (a) = n
For the system of non-homogeneous linear equations AX = B, a is a matrix of order m * n, let rank (a) = R, then
When A.R = m, the system AX = B has a solution, and when b.R = n, the system AX = B has a unique solution
When C.M = n, the system AX = B has a unique solution D.R

Ax = B has solution R (a) = R (a, b)
When r = n, the equations may not have solutions
When r = m, because M = R (a)

Party A and Party B process 1500 parts. It is known that Party A processes 150 more parts than Party B. how many parts have they each processed?

A processed: (1500 + 150) △ 2 = 825
B: 825-150 = 675

7x-12(5/3-1/2)=8-2/3(x-9)

7x-12(5/3-1/2)=8-2/3(x-9)
7X-20+6=8-2X/3+6
7X-14=14-2X/3
21X-42=42-2X
23X=84
X=4

There are 1400 tons of grain in the three warehouses. The weight ratio of grain in warehouse A to warehouse B is 3:4, and the weight ratio of grain in warehouse B to warehouse C is 6:7

A: B = 3:4 = 9:12
C: B = 7:6 = 14:12
A: B: C = 9:12:14
Each: 1400 (9 + 12 + 14) = 40 (tons)
A: 40x9 = 360 (tons)
B: 40x12 = 480 (tons)
C: 40x14 = 560 (tons)

125 minus 23 is 5. What's the number?

Let this number be X. from the meaning of the question, we can get: 125-23x = 5, & nbsp; & nbsp; & nbsp; 23x = 120, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 180. A: this number is 180

15 times 15,

15*15=10*20+25=225
All double digits ending in 5 can be calculated by subtracting 5 from the number, multiplying it by 5 and adding 25
For example, 25 * 25 = 20 * 30 + 25 = 625
35*35=30*40+25=1225
If you don't believe me, the results are all right and convenient. It was written in a magazine I saw in high school

It is known that A1 * A2 * A3 is equal to 27 in the equal ratio sequence {an}. If the common ratio Q of {an} is greater than 1, and A1 plus A2 plus A3 is equal to 13, find the sum of the first five terms of {an}

a1³q³=27
q>1
So A2 = a1q = 3
a1+a2+a3=3/q+3+3q=13
3q²-10q+3=0
（3q-1）（q-3）=0
So q = 3
a1=1
a1+a2+a3+a4+a5=1+3+9+27+81=121