If we know that the square of a plus the square of B plus the square of C is equal to ab plus BC plus AC, then the relation between ABC is【

a2+b2+c2-ab-ba-ac=0
Multiply both sides of the equation by two
2a2+2b2+2c2 - 2ab -2bc -2ac=0;
It can be matched
(a-b)2+(b-c)2+(a-c)2=0;
So a = b = C

RELATED INFORMATIONS

1. Who knows the summation formula of second order arithmetic sequence?
2. If a is not equal to 0, then the equation of X + the square of Y + ax ay = the image represented by 0 On X-axis symmetry On Y-axis symmetry On the symmetry of the line X-Y = 0 On the symmetry of the line x + y = 0
3. Is there a formula for summation of second order arithmetic sequence? Is the latter minus the former is the arithmetic sequence, how to find the sum of the original sequence?
4. To solve the equation about X, the square of x minus 2x plus 1 equals K (the square of x minus 1) (k is not equal to 0)
5. Given the complex number Z, find Z + Z square + Z three square + Can we use the summation formula of real number equal ratio sequence to sum?
6. If the solutions of the equations 2x-y23 and x-2y equal to a satisfy that x + y is greater than 0, then the value range of a is a, and the value range of a is a
7. Summation formula of permutation and combination
8. 2X + 3Y = k the sum of solutions X and y of the system of linear equations {3x-4y = K + 11} with respect to X and Y is known to be equal to 3, and the value of K is obtained The method is as simple as possible
9. What is the formula for horizontal summation?
10. Given that x minus 1 / x equals 2, how much is x square minus 1 / x square? Specific and accurate answers and processes are needed
11. What is the summation formula of arithmetic sequence
12. Judge whether the triangle whose three sides are 2n ^ 2 + 2n, 2n + 1, 2n ^ 2 + 2n + 1 is a right triangle Judge whether the triangle whose three sides are 2n ^ 2 + 2n, 2n + 1, 2n ^ 2 + 2n + 1 (n is greater than 0) is a right triangle Remember to prove which is the hypotenuse! To prove why that's a hypotenuse
13. Let Sn = - 1 + 3-5 + 7 - +(- 1) n (2n-1), then SN=______ ．
14. Judge whether the triangle with three sides of n ^ 2-1, 2n, n ^ 2 + 1 (n > 1) is a right triangle? And explain the reason
15. Sn = 1 / 2 + 3 / 2 ^ 2 + 5 / 2 ^ 3 +... + (2n-1) / 2 ^ n sum My foundation is not good, please try to be more detailed,
16. Try to judge: are triangles with 2n * n + 2n, 2n + 1, 2n * n + 2n + 1 sides right triangles?
17. Calculate 1 + (1 + 2) + (1 + 2 + 3) + +（1+2+3+… +n）．
18. Prove: square of M - square of N, 2Mn, square of M + square of N, (M and N are natural numbers, and M is greater than N and greater than 0) is the side length of right triangle
19. Calculate 1 + (1 + 2) + (1 + 2 + 3) + +（1+2+3+… +n）．
20. Is a triangle whose three sides are square of a = m - square of N, B = 2Mn, C = square of M + square of n (M greater than n greater than o) a right triangle