X square - y square + 5x + 3Y + 4

X square - y square + 5x + 3Y + 4

x²-y²+5x+3y+4
=（x²+5x+6.25）-（y²-3y+2.25）
=（x+2.5）²-（y-1.5）²
=（x+2.5+y-1.5）（x+2.5-y+1.5）
=（x+y+1）（x-y+4）

The number a is 120, the number B is 100, what percentage is the number a? What percentage is the number a more than the number B? What percentage is the number b less than the number a?

Number a is 120 of number B △ 100 = 120%
Number a is 120% - 1 = 20% more than number B
Number B is less than number a (120-100) △ 120 ≈ 16.7%

If the sum of nonnegative numbers is equal to 0, then every nonnegative number is 0. If the sum of nonnegative numbers is equal to 0, then every nonnegative number is 0
(radical 3-x) + | 2-y | = 0. Find the value of X + y
(radical 2A + b) + |b-a | = 0. Find the value of a + B |

Question 1: 3-x = 0, and 2-y = 0, so x = 3, y = 2, so x + y = 5
The first problem: 2A + B = 0 and B-A = 0, the simultaneous equations are solved a = b = 0, so | a + B | = 0
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The average of the three numbers of a, B and C is 84. The ratio of a, B and C is 3:4:5. What are the numbers of a, B and C?
Such as the title

84*3/(3+4+5)=21
A: 21 * 3 = 63
B: 21 * 4 = 84
C; 21 * 5 = 105

In a right triangle, the sum of the lengths of the two right sides is 10, when the lengths of the two right sides are 1______ 、______ The area of the right triangle is the largest

Let one of the right angles be x, then the other be 12-x, and the area of the triangle be s, s = 12x (10-x) = - 12 (x2-10x) = - 12 (X-5) 2 + 252, ∵ a = - 12 ＜ 0, ∵ s has the maximum value. When ∵ x = 5, the maximum value is s = 18, that is, the maximum area of the triangle is 252

60% of a number is 120. What is 3 / 10 of this number

Let this number be X
60%x=120
x=200
3x of 10 = 200 * 3 of 10 = 60

Let a be an mxn matrix and R (a) = m. It is proved that the system of linear equations AX = B must have solutions

In the case of non-homogeneous equations without solutions, the rank of coefficient matrix is different from that of augmented matrix
The rank of the coefficient matrix in the question is m, and there are only m equations, so the rank of the augmented matrix can not be greater than m, and the rank of the augmented matrix is greater than the coefficient matrix, so the rank of the augmented matrix is also m, so this non-homogeneous equation system must have a unique solution

Party A and Party B process 1500 parts respectively. Because Party B adopts new technology, the number of parts processed by Party B is three times that of Party A at the same time. Therefore, Party B processes less than 20 hours than Party A. how many parts do they process each hour?

Let a process x per hour, then B process 3x per hour. According to the meaning of the problem, 1500x = 15003x + 20, the solution is x = 50. Test: when x = 50, 3x = 3 × 50 ≠ 0, so x = 50 is the root of the original fractional equation, and conforms to the meaning of the problem. Answer: a processes 50 per hour, B processes 150 per hour

1、7x+5=8（x-1)+2

7x+5=8(x-1)+2
7x+5=8(x-1)+2
7x+5=8x-8+2
7x+5=8x-6
5+6=8x-7x
x=11

A total of 340 tons of grain are stored in warehouse A and warehouse B. If warehouse a uses 1 / 3 of the stock and warehouse B uses 1 / 4 of the stock, then the remaining stock weight of the two warehouses is equal. How many tons are there in warehouse A and warehouse B?

13920522600,
The ratio of a to B is: (1-1 / 4): (1-1 / 3) = 9:8
Grain storage in warehouse A: 340 × 9 / (9 + 8) = 180 (T)
Grain storage in warehouse B: 340 × 8 / (9 + 8) = 160 (T)