How much is the square of one number minus the square of another? Is there any formula that can be used? What if it's an addition? What's the sum of the square of one number plus the square of another?

a^2-b^2=(a+b)(a-b)

144 is (whose) square

For the system of equations x + 2Y = 3A + 1,2x + y = 4 satisfying X-Y > 0, then the value range of a is

2X + y = 4 minus x + 2Y = 3A + 1
x-y=3-3a>0
3a

Please fill in four different numbers in the four boxes of Formula 1 □ × 1 □ = 1 □ × 1 □, so that the equal sign holds. Q: what is the sum of the four numbers?

1 (2) × 1 (5) = 1 (0) × 1 (8), 2 + 5 + 0 + 8 = 15

The distance between vertices is 6, and the asymptote equation is the standard equation of hyperbola with y = ± 1 / 3x

Focus on X axis X ^ 2 / 9-y ^ 2 = 1
Focus on Y axis Y ^ 2 / 9-x ^ 2 = 1

Please add + or - between the numbers 3 / 2, 5 / 6, 7 / 12, 9 / 20, 11 / 30, 13 / 42, 15 / 56 so that the result of the formula is one and one eighth
3/2=2+1/12=1/1+1/2 5/6=3+2/23=1/2+1/3
7/12=4+3/3*4=1/3+1/4……

3/2-5/6+7/12-9/20+11/30-13/42+15/56

c/a

Necessary and sufficient conditions

Seeking 500 mixed questions of multiplication, division, addition and subtraction in mathematics of grade two of primary school

.1/3*(5*(2/3))
2.(1+37%)*20
3.35/2*75%
4.30*(50/2)
5.(54+10%)/20
6.(25/3*18)*30%
7.(2+70%)*40
8.1/7*(98*(1/4)*2)
9.25%*((23+2%)*4)
10.(30+20%)/2
11.12*3/(25+20%)
12.30/(3+40%)
13.27/8*16*10%
14.(2/3)*(3+6)*(1/2)
15.45*(1/9)*24
16.(35+10%)*27
17.(45+50%)*3*1/2
18.(43*20%)+(3*(1/9))
19.27*(9*(1/3))*5%
20.14*15%+25*8*(1/4)
21.7*(1/2)/49
22.(1+48%)*2
23.(4*8-12)*50%
24.(48/60%)/10
25.63*(1/7)*30%
26.(0.75+0.2)/0.25*25% 12/0.75+7.2/2.4
27.605*8+3.5-44 10.9-(6.6+0.125/12.5%)
28.980-9.8)*0.6-2.12 (0.125*8-0.5)*4
29.1+0.45/0.9-0.75 168.1/(4.3*2-0.4)
30.1.21*42-(4.46+0.14) 1375+450/18*25
31.18/1.5-0.5*0.3
32.1.9-1.9*(1.9-1.9)

Is there any real root of the equation x + AX-1 = 8? If so, how many real roots?

x^2+ax-9=0
a^2+36>0
There are two real roots

How to calculate the formula of one variable linear regression equation

Suppose that the linear regression equation is y = ax + B (1)
a. B is regression coefficient, which should be determined by observation data (x1, X2,..., xn and Y1, Y2,..., yn)
Therefore, we construct Q (a, b) = ∑ (I = 1 - > n) [Yi - (Axi + b)] ^ 2 (2)
Let Q (a, b) take the minimum value of a, B as the solution
Let: &; Q / &; a = 2 ∑ (I = 1 - > n) [Yi - (Axi + b)] (- Xi) = 0 (3)
∂Q/∂b= 2Σ(i=1->n)[yi-(axi+b)] = 0 (4)
The regression equation (1) is determined by solving a and B according to (3) and (4)
a Σ (Xi)² + b Σ Xi = Σ Xi Yi (5)
a Σ Xi + b n = Σ Yi (6)
From (5) (6) to solve a, B is. / /: this step is omitted

How much is the square of one number minus the square of another? Is there any formula that can be used? What if it's an addition? What's the sum of the square of one number plus the square of another?