20.3-3 / 11-3.7-14 / 17-6.3 (simple calculation,

20.3-3 / 11-3.7-14 / 17-6.3 (simple calculation,

20.3-3/11-3.7-14/17-6.3
This should be 3 / 17, right?!
20.3-3/17-3.7-14/17-6.3
=20.3-3/17-14/17-3.7-6.3
=20.3 - (3/17 +14/17) - (3.7+6.3)
=20.3 - 1- 10
=20.3-11
=9.3

P is a point on the line AB, PA: Pb = m: n, ab = a, then the length of AP is?

a*(m/(m+n))

Factorization factor X3 + 3x2 + 3x + 98

x^3+3x^2+3x+9 =x^2(x+3)+3(x+3) =(x+3)(x^2+3)

Prove that a parallelogram with equal diagonal is a rectangle
A parallelogram with three right angles is a rectangle~

In the parallelogram ABCD, AC = BD
According to the characteristics of parallelogram: the opposite sides are equal: BC = ad, ab = ab
So: △ ABC ≌ △ bad
It can be seen that: ∠ ABC = ∠ bad, and ∠ ABC + ∠ bad = 180 degree
So: ∠ ABC = ∠ bad = 90 ° that is, an angle of a parallelogram is a right angle
ABCD is a rectangle
∠A=90°,∠B=90°,∠C=90°
Because: a + B + C + D = 360 degree
So: ∠ d = 360 °～ a ～ B ～ C = 360 °～ 90 °～ 90 °～ 90 ° = 90 °
That is, the four corners of the quadrilateral ABCD are right angles, so ABCD is a rectangle

5 / 14 △ x = 6 × 5 / 12,

(5/14)/x=6*5/12
(5/14)*(1/x)=5/2
5/(14x)=5/2
5*(14x)=5*2
14x=2
x=1/7

Find the tangent length from point P (5,3) to circle & nbsp; x2 + y2-2x + 6y + 9 = 0

From x2 + y2-2x + 6y + 9 = 0, we know the center coordinates a (1, - 3), radius r = 1 and ∵ P (5,3) ∵ is | PA | = (5 − 1) 2 + (3 − (− 3)) 2 = 52 and ∵ radius is perpendicular to tangent. Let the tangent length from point P (5,3) to circle be D, then d = | PA | 2 − R2 = 52 − 1 = 51 ∵ the tangent length from point P to circle be 51

In rational numbers, what is an integer instead of a positive number? What is a fraction instead of a negative fraction? What is the smallest positive integer

Negative integer, positive fraction, 1

If the quadratic function y = x & sup2; - 2x + 3 has a maximum value of 3 and a minimum value of 2 when 0 ≤ x ≤ m, then the value range of real number m is
If t ≤ x ≤ T + 1 is known, the minimum value of function y = x & sup2; - 2x-1 can be obtained

Y = (x-1) ^ 2 + 2 & nbsp; when x = 1, y min = 2, y max = 3, so 0 ≤ x ≤ 2
   1≤m≤2 
y=(x-1)^2-2
Y min = - 2

If the reciprocal of 3 / 3 of a and 2a-9 of 3 are opposite to each other, what is a equal to
RT

-a/3=(2a-9)/3
-a=2a-9
a=3

Solve the following equations: (1) x + y = 8,5x + 1 = 2 (x + y); (2) 2x + 5Y = 12,2x + 3Y = 6

1. X + y = 8, 5x + 1 = 2 (x + y) x + y = 8, x = 8-y brings in 5x + 1 = 2 (x + y); 5 (8-y) + 1 = 2 [(8-y) + y]; (40-5y) + 1 = 2 * 8; (40-5y) + 1 = 16; 40-15 = 5Y; 25 = 5Y; y = 5 x + y = 8; X + 5 = 8, we get x = 32, 2x + 5Y = 12 ----- ① 2x + 3Y = 6 ----- ②