1.10.12.25.37.54.102.417.23.398 which is composite? Which is prime

1.10.12.25.37.54.102.417.23.398 which is composite? Which is prime

1 is neither composite nor prime, 10, 12, 25, 54, 102, 41, 7398 are composite, 37, 23 are prime

In the form of prime sum: 21=______ +______ ．

21 = 2 + 19, so the answer is: 2, 19

Prime + prime = 21 what is a prime?

2+19

What is the square of XY minus the square of X, y

The square of X - the square of x-x + y = - 2y-x = - 2 is the square of (Y-X) = 4
Divide both sides by 2 to get: (x squared + y squared) / 2-xy = 2

Fifth grade volume 2 oral arithmetic practice
There should be fractions and decimals, and the interval between the title and the body should be larger
I want you to say it

17 × 40 = 100-63 = 3.2 + 1.68 = 2.8 × 0.4 = 14-7.4 = 1.92 △ 0.04 = 0.32 × 500 = 0.65 + 4.35 = 10-5.4 = 4 △ 20 = 3.5 × 200 = 1.5-0.06 = 0.75 △ 15 = 0.4 × 0.8 = 4 × 0.25 = 0.36 + 1.54 = 1.01

A system of equations about X and Y {X-Y = 2A x + 3Y = 1-5a x-2y

First, observe the topic and ask for the value range of A
In the system of equations with X and y as unknowns, a is known
So consider using the equations to express X and y with a respectively
Then the range of a can be obtained by substituting the following inequality about X and y
X-Y=2a
X+3Y=1-5a
We obtain x = (1 + a) / 4, y = (1-7a) / 4
Substituting the inequality, we get (1 + a) / 4-2 * (1-7a) / 4 = (15a-1) / 4

Use the five numbers 2, 3, 5, 6 and 0 to form the formula of multiplying three digits by two digits. The maximum product is

620*53=32860=530*62

If there are two intersections between the line L passing through the origin and the hyperbola y ^ 2-x ^ 2 = 1, then the slope of the line L is in the range of
Thank you for your hard work!

The line passing through the origin L: y = kx
There are two intersections with hyperbola y ^ 2-x ^ 2 = 1
Y = KX into hyperbola
kx²-x²=1
x²(k-1)=1
k-1>0
k>1
The range of slope k of line L is k > 1

What is 1 + 1 + 2 + 2 + 3 + 3 + 4 + 4 + 5 + 5. + 99 + 99 + 100 + 100

2✘（1+100）✘50=10100

The roots of the quadratic equation AX2 + BX + C = 0 (a > 0) with one variable when △ > 0, △ = 0, △ ＜ 0
The roots need to be represented by letters, and the solutions of AX2 + BX + C ＞ 0 (a ＞ 0) and AX2 + BX + C ＜ 0 (a ＞ 0) when △ > 0, △ = 0, △ ＜ 0

The quadratic equation AX2 + BX + C = 0 (a ≠ 0) has real number solutions, including the equation has two equal or unequal real number roots, all △≥ 0. The discriminant of roots is for quadratic equation of one variable, so its use condition is a ≠ 0. The discriminant of roots of quadratic equation AX2 + BX + C = 0 (A & gt; 0) is △ = b2-4ac; & n