Question

If (a/b) = (c/d), which of these statements is not true?

Answer 1

ac = bd, given that b and d are not 0.

b/a = d/c, given that a, b, c, and d are not 0.

ad = bc, given that b and d are not 0.

(a + b)/b = (c + d)/d, given that b and d are not 0.

Answer 2

cna you tell me which two statements contradict each other from the get go?

Answer 3

im not too sure

Answer 4

take a look, which two are almost identical?

Answer 5

the first and third?

Answer 6

good, so now since they are so close let's focus on those two. Are you able to make \[\frac{a}{b}=\frac{c}{d}\] look anything like either of those? If so, how?

Answer 7

the third one. . i think

Answer 8

Can you show me how?

Answer 9

ac=bd
because a/b=c/d then a=(cb)/d and ac=(c^2b)/d which is not bd because when you substitute, bd=(d^2a)/c, unless d=c and a=b
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a/b=c/d, 1/b=c/da, 1=cb/da, 1/c=b/da, d/c=b/a; b/a=d/c
number 2 is true
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ad=bc when you pass d from dividing c to multiply a, and you pass b from dividing a to multiply c; a/b=c/d, ad/b=c, ad=bc
number 3 is true
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(a+b)/b=(c+d)/d= a/b+b/b=(a/b)+1, c/d+d/d= (c/d)+1, a/b+1=c/d+1, a/b+1-1=c/d, a/b=c/d
number 4 is true
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making a balance of probability in which the 2,3 and 4 have a 100% chance of being true, while number 1 is only true when a=b and c=d (which, considering we have an infinite amount of numbers would be dividing 1 by infinity) I can confidently say that the one that is not true must be ac=bd