Write two rational numbers so that their sum and product are both positive numbers. Please state the sign of two rational numbers

Write two rational numbers so that their sum and product are both positive numbers. Please state the sign of two rational numbers

The sign of two rational numbers is positive

On factorization
a(a²-a-1)+1

a(a^2-a-1)+1
=a^3-a^2-a+1
=a^2(a-1)-(a-1)
=(a-1)(a^2-1)
=(a-1)^2(a+1)

It is known that the vertex of quadratic function image is (- 1,0), and it is over (0,3 / 2)
(1) The expression of quadratic function
(2) Does the line y = - 2x + 1 intersect this parabola? If so, find the coordinates of the intersection. If not, explain the reason

Let the vertex formula be y = a (x + 1) ^ 2
(0.3 / 2) to get a = 3 / 2
That is, y = 3 / 2 (x + 1) ^ 2
(2) Y = - 2x + 1 to y = 3 / 2 (x + 1) ^ 2
-2x+1=3/2x^2+3x+3/2
3x^2+10x+1=0
3(x+5/3)^2=25/3-1=22/3
(x + 5 / 3) = (/ -) radical 22 / 3
So there is an intersection, and the coordinates are ((- 5 (+ / -) radical 22) / 3, (13 (- / +) 2 radical 22) / 3)

How to solve x-20 ≤ 0? I need process

x²-8x-20≤0
(x+2)(x-10)≤0
X + 2 ≥ 0, X-10 ≤ 0, the solution is - 2 ≤ x ≤ 10
Or x + 2 ≤ 0, X-10 ≥ 0, no solution
In conclusion, the solution set is - 2 ≤ x ≤ 10

Given the parabola y = - x ^ 2 + MX-1, when m changes, the trajectory equation of the parabola vertex is?

y
= -x² + mx - 1
= -(x - m/2)² + m²/4 - 1
So vertex coordinates (M / 2, M & # / 4 - 1)
So the trajectory equation of vertex is y = x & # 178; - 1

On the road parallel to the railway, one person rides a bicycle at the speed of 5 meters per second, and the other walks at the speed of 2 meters per second. A train runs on the railway at the speed of 57.6 kilometers. It takes 8 seconds for the train to meet the cyclist and leave the cyclist. How many minutes does it take for the train to catch up with the pedestrian and surpass the pedestrian?
The train speed is 57.6 km / h

In this question, it takes 8 seconds for the train to overtake the cyclist. After conversion, if the speed of the train is known to be 16 m / s, the train will pass 16 * 8 = 128 m, and the cyclist will pass 5 * 8 = 40 m. because it is an encounter, it means that the train and the cyclist are facing each other, that is, the length of the train is 128 + 40 = 168 M

Find the trajectory equation of the moving point whose distance to point a (1,1) is equal to the distance to x-axis

Set to (x, y)
Then √ [(x-1) & sup2; + (Y-1) & sup2;] = | y|
square
x²-2x+1+y²-2y+1=y²
x²-2x-2y+2=0
y=x²/2-x+1

One
Try to explore the equation AX & sup2; + BX + C = 0 (a ≠ 0) by using the root formula of quadratic equation of one variable
(1) The condition of two opposite numbers
(2) Two reciprocal conditions
2
The equation x & sup2; - (K + 2) x + 2K = 0 for X is known
If one side of the isosceles triangle ABC a = 3, and the lengths B and C of the other two sides are exactly the two roots of the equation, find the perimeter of △ ABC
Please indicate the process, thank you

1 (1) the product of two = c-a0
Or C = 0
2) c\a=1 b*b-4ac>0
Or a = - B-C or a = b-c
One of 2 (1) B, C is 2, and the other is k, so 1

How many square kilometers is Singapore's territory and how many million people are there?

699.4 square kilometers, 3.608 million citizens and permanent residents, and 4.48 million permanent residents

Newton's law and formula of universal gravitation?

The content of the law is as follows: any two particles attract each other through the force in the direction of the connecting line. The magnitude of the gravity is directly proportional to their mass product, inversely proportional to the square of their distance, and has nothing to do with the chemical nature or physical state of the two objects and the intermediate matter. The formula is: F = g * m1m2 / (R * r) (g = 6.67 × 10 ^ - 11n · m ^ 2 / kg ^ 2)