The square roots of nonnegative numbers are opposite numbers, right

The square roots of nonnegative numbers are opposite numbers, right

Yes, because:
∵（-3）²=9
And ∵ 3 & sup2; = 9
The root 9 = ± 3

If the two diagonals of a parallelogram are 8 and 12, then its side length cannot be taken as () a.6 B.7 c.8 d.10
What's the idea?
If the two diagonals of a parallelogram are x and y, then its side length cannot be ()
Please write the reason clearly,
I have three questions,
Don't give any points for less answers

D
The two diagonals of a parallelogram are bisected,
Two diagonals divide the parallelogram into four triangles. Two sides of each triangle are half of the two diagonals
The sum of the two sides of a triangle is greater than the third side, and the difference between the two sides is less than the third side
If the two diagonals of a parallelogram are x and y, then its side length cannot be (≥ (x + y) / 2), or ≤ (X-Y) / 2

1 / 2 (x-3) ^ 2 = 8, solve the equation with proper method

（x-3)^2=16
x-3=4 x-3=-4
x=7 x=-1

Given the points a (- 3,5), B (2,15), find a point P on the straight line L: 3x-4y + 4 = 0 to minimize | PA | + | Pb |

In fact, let p 'be a point different from P on L, then | p' a | + | p 'B | = | p' a | + | p 'B | > a' a 'B | = | PA | + | Pb |. Let a' (x, y), then Y − 5x + 3 · 34 = − 1, and & nbsp; 3 · x − 32-4y + 52 + 4 = 0, the equation of x = 3, y = - 3, х a '(3, - 3), х line a' (b) is 18x + y-51 = 0. From 3x − 4Y + 4 = 018x + y − 51 = 0, the equation of x = 83y = 3, х P (83,3) is obtained

(x + 1) (x + 2) (x + 3) (x + 4) (x + 5) (x + 6) (x + 7) (x + 8) (x + 9) (x + 10) please simplify
I'm talking about simplification
In the form of x ^ 10 + ax ^ 9 + BX ^ 8 + CX ^ 7 +... + n

x^10+55*x^9+1320*x^8+18150*x^7+157773*x^6+902055*x^5+3416930*x^4+8409500*x^3+12753576*x^2+10628640*x+3628800

It is proved that the value of - x ^ 2 + 8x-18 is always less than 0

-x²+8x-18
　　=-x²+8x-16-2
　　=-(x²-8x+16)-2
　　=-(x-4)²-2
　　∵(x-4)²≥0
　　∴-(x-4)²≤0
　　∴-(x-4)²-2

If the difference between the reciprocal of 1 and 1-x is equal to the reciprocal of 1-x, then x=______ ．

According to the meaning of the question, the fractional equation is listed: 1-11 − x = 11 − x, the denominator is removed to get: 1-X-1 = 1, and the solution is x = - 1. It is the solution of the original equation after testing. Therefore, the answer to this question is: x = - 1

It is known that the sum of an integral and (2x2 + 5x-2) is (2x2 + 5x + 4), then the integral is ()
A. 2B. 6C. 10x+6D. 4x2+10x+2

According to the meaning of the question, (2x2 + 5x + 4) - (2x2 + 5x-2) = 2x2 + 5x + 4-2x2-5x + 2 = 6

Why can't we use dichotomy to get the approximate value of zero point when the function image is discontinuous

It can't be approximated when it's discontinuous and has no function value

The parabola y = x & # 178; + BX + C has the vertex P and the axis of symmetry x = 2. If there are two intersections A and B between the parabola and the X axis, what is the value of C,
The triangle PAB is an isosceles right triangle

-B / 2A = 2, a = 1, so B = - 4
Let the intersection of the axis of symmetry and X be m,
When the triangle PAB is an isosceles right triangle, ab = 2pm
AB = √ (b ^ 2-4ac) / | a | = √ (16-4c) = 2 √ (4-C) (obtained by subtracting two quadratic equations of one variable)
PM = | 4-8 + C | = | C-4 | = 4-C, (substituting x = 2 into the analytical formula to get the vertex ordinate, but because the opening is upward and the vertex is below the X axis, the vertex ordinate is negative, so the length is opposite.)
2√(4-c)=2（4-c)
√(4-c)=4-c
(4-c)^2-(4-c)=0
(4-c)(4-c-1)=0
C = 4 or C = 3
The test shows that when C = 4, there is only one intersection point between parabola and x-axis, so C = 3