without expansion verify that | 2a   2b  2c |\n                              | a+b  2b  b+c|  = 0\n                              | a+c  b+c 2c |
129335
Divide R1 by 2a\n| 1 b/a c/a |\n| a+b 2b b+c |\n| a+c b+c 2c |\n\nMultiply R1 by (a+b), then subtract R2-R1 and put this in R2\n| 1 b/a c/a |\n| 0 2b-[b(a+b)/a] b+c-[c(a+b)/a] |\n| a+c b+c 2c |\n\nMultiply R1 by (a+c), then subtract R3-R1 and put this in R3\n| 1 b/a c/a |\n| 0 2b-[b(a+b)/a] b+c-[c(a+b)/a] |\n| 0 b+c-[b(a+c)/a] 2c-[c(a+c)/a] |\n\nSimplify\n| 1 b/a c/a |\n| 0 b-(b^2/a) b-(bc/a) |\n| 0 c-(bc/a) c-(c^2/a) |\n\nDivide R2 by b and divide R3 by c\n| 1 b/a c/a |\n| 0 1-b/a 1-c/a] |\n| 0 1-b/a 1-c/a) |\n\nSubtract R3-R2 and put the answer in R3\n| 1 b/a c/a |\n| 0 1-b/a 1-c/a] |\n| 0 0 0 |           =0
665357
decimal 2+2=4\nbinary 2+2=10+10=100\noctal    2+2=4\nhexadecimal  2+2=4\n\n\nand if the base is 3 then  2+2=10
61926
u can't devide by (a-b) as (a-b)=0
88785
Cross multiply\n(x-2b)c = (x-2c)b  Multiply each side out using the distributive property\nxc - 2bc = xb - 2cb Since you are solving for x move all the terms that have an x to one side and all the terms that do not have an x to the other side.\nSo add 2bc to each side and subtract xb from each side\nxc - xb - 2bc + 2bc = xb - xb - 2bc + 2bc\nxc - xb = 0  Factor an x from the left side\nx(b-c) = 0\nEither x = 0 or b-c = 0\nso x = 0 or b = c\nIf b does not equal c then x must be zero.\nIf b does equal c, then x can be anything.\nAlso, note that b and c cannot equal zero because then you would be dividing by zero.  Dividing by zero is undefined.
312222
Given a+b=c\n\n4(a+b-c)=3(a+b-c)is true only because a+b-c=0.\nIf a+b-c is not equal to zero, 4(a+b-c) is NOT equal to 3(a+b-c).\n\nCancellation of a+b-c on both sides means dividing both sides by a+b-c.\n\nas a+b-c=0, division is not allowed.\nCancellation is allowed only when a+b-c is not equal to 0.\n\n4/0 and 3/0 are not meaningful.\nAlso, 4/0 and 3/0 are not equal to infinity.\n4(a+b-c)=0 as a+b-c=0\n4(a+b-c)/(a+b-c) is 0/0 equal to infinity.\n\nPlease note that in the very definition of division, we say that division by zero is not defined.
636760
A=  C - B divided by (x + y).\nB= C - A divided by (x + y).\nC= A*x + B*y\n\n* = multiply
498016
The only case that I could think of that A is not equal to B where AC=BC is when C=0.  Other than that A must equal B for the expression to be valid
544956
(A^2+2ab+b^2)/(a+b) + (a^2-b^2)/(a-b) + (a-b)/(a+b)/(a^2-b^2)/a+b)\n(a+b)^2/(a+b)+(a+b)(a-b)/(a-b)+ (a-b)/(a+b)*(a+b)/(a^2-b^2)\na+b+a+b+(a-b)/((a+b)(a-b))\n2a+2b+1/(a-b)\n\nif I got all the ( ) in the right places.
288911
In (a+b)(a-b)=b(a-b)\n\nyou divided by (a-b)\n\nHowever a-b = 0 so you can't divide by it
177827
ya it is a^2 +b ^2 +2abcos(c)
377239
5a+6b-3a+b=?\nSimplified= (2a+7b=?)  or (2a = -7b) or (7b = -2a)\nThey are all the same\n\n15x-3y-7x-4y=?\nSimplified = (8x-7y=?)  or (8x = 7y) or (-8x = -7y)\n\n15m-17n-23m+25n=?\nSimplified -8m+8n=? or (8n=8m) or (n=m)
302273
GIVEN:\n\nA. <1 + <2 =180\n\nB. <1 = <2 + 36\n\nsubstitute\n\n(<2 + 36) + <2 =180\n\n2<2 + 36 =180\n\nsubstract 36 from both sides\n\n2<2 + 36 -36 =180 -36\n\ndivide 2 on both sides\n\n2<2 = 144\n\n(2<2)/2 = 144 /2\n\n<2 =72\n\nsubstitute 72 for <2 in equation B.\n<1 =<2 + 36\n<1 =72 + 36\n\n<1 =108
664297
2[w+ {2w+8}]= 64\n3w+8 = 32\nw= 8 \nyour are right
308954
[-b +/-  sqrt(b^2-4ac)]/(2a)
542071
c^2 = a^2+ b^2 - 2abcosC\n\nC = 90\n\nA =  25\n\nB = 65
1387
We have:\n(1) A+B=25\n(2) B+C=29\n(3) D=14\n(4) D=(A+C)/2\n\n(3) and (4) -> (5) A+C=28\n(1) + (2) - (5) -> 2*B=26 -> (6) B=13\n(1) and (6) -> A=12\n(2) and (6) -> C=16
183119
x = -b +(or)- sqrt(b^2 - 4ac)\n    -------------------------\n               2a