If and only if one of the two real roots of the real coefficient equation x ^ 2 + ax + B = 0 is larger than 1 and the other is smaller than 1 The answer is a + B + 1

If and only if one of the two real roots of the real coefficient equation x ^ 2 + ax + B = 0 is larger than 1 and the other is smaller than 1 The answer is a + B + 1

Weida theorem
x1+x2=-a
x1*x2=b
Yes (x1-1) (x2-1)

In rectangle ABCD, e is the midpoint of ad to C angle. F is the midpoint of CE. The area of rectangle is 48, and BFD of triangle is obtained

If be is connected, then s ⊿ BCD = s ⊿ BCE = (1 / 2) s rectangle ABCD = 24;
If de / ad = de / BC = 1 / 2, then s ⊿ CDE = (1 / 2) s ⊿ BCD = 12
Point F is the middle point of CE. Similarly, s ⊿ CDF = (1 / 2) s ⊿ CDE = 6; s ⊿ BCF = (1 / 2) s ⊿ BCE = 12
Therefore, s ⊿ BFD = s ⊿ bcd-s ⊿ bcf-s ⊿ CDF = 24-12-6 = 6

The quadratic function y = 1 / 2x ^ 2-x-4 is known
Find the vertex coordinate, the symmetry axis of the function image and the intersection coordinate of the image and the coordinate axis, and draw the general image of the function

A: y = (1 / 2) x ^ 2-x-4
y=(1/2)(x^2-2x+1)-1/2-4
y=(1/2)(x-1)^2-9/2
The vertex is (1, - 9 / 2), and the axis of symmetry x = 1
The intersection point with X axis is (- 2,0), (4,0)
The intersection point with y axis is (0, - 4)
The image is as follows:

In the checkerboard of the picture, Party A and Party B each put a chess piece, requiring that the two pieces are not in the same row or column?

A: 5 × 5 = 25 (species), B: 5 × 5 - 9 = 16 (species), 25 × 16 = 400 (species); a: there are 400 different methods

Can you translate the function y = - 3 / 4x ^ 2 up and down properly to make the new image pass through the point (3, - 18)? Tell the translation direction and distance

Yes, find Z
-18 = -3/4*9 + z

Simplified evaluation: B / (a-b) * (A3 + ab2-2a2b) / B3 / (b2-a2) / (AB + B2), where a = 2 / 3, B = - 3
If you get it right, you'll get extra points

The original formula is: B / (a-b) × (A & # 179; + AB & # 178; - 2A & # 178; b) / B & # 179; / (B & # 178; - A & # 178;) / (AB + B & # 178;) = B / (a-b) × a (A & # 178; - 2Ab + B & # 178;) / B & # 179; / (a + b) (B-A) / b (a + b) = AB (a-b) &# 178

Abcd-cdc = ABC (vertical) for a, B, C, D why?

1098-989 = 109, a, B, C, D are 1,0,9,8 respectively

There is a right angled trapezoid whose bottom is 20 cm. If the top is increased by 5 cm, it becomes a square

20-5 = 15cm to calculate the trapezoidal bottom
Because the sides of a square are the same, so (15 + 20) times 20 divided by 2
=35 times 20 divided by 2
=700 divided by 2
=350CM2

In △ ABC, if a: B: C = 3:4:5, and the perimeter is 60cm, what is the area?

a=60×3÷(3+4+5)=15
b=60×4÷(3+4+5)=20
c=60-a-b=25
Then a & # 178; + B & # 178; = C & # 178;
So it's a right triangle
So area = AB / 2 = 150 square centimeters

Imaginative composition the horse of the future
Be quick!

It's still in the mare's stomach