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cnebbear
I think my math book is wrong...but I don't know. Could someone check and if it's not wrong, explain it to me?
hmm what is your math book answer?
That is the math book answer
hmm and what is your answer?
I know this can't be right but I got x=2.5. I don't understand how they randomly got the extra 2 when it should be a 9.
ok.. i also have got a different answer but not sure.. so can you put steps how you solve it?
it looks like its just a typing error, try asking or calling your teacher
81x - 21x = 24 60x = 24 x = 24/60 = 2/5
Yeah it's about evaluating determinants of a matrix. How I solved the problem was: (0)(1)(3)+(7)(2)(0)+(9)(x)(9) (0)(1)(9)-(9)(2)(0)-(3)(x)(7) 0+0+81x-0-0-21x=24 60x=24 x=2.5
See http://www.wolframalpha.com/input/?i=det+%7B+%7B0%2C7%2C9%7D%2C%7B0.4%2C1%2C2%7D%2C%7B0%2C9%2C3%7D%7D x= 0.4 so there must be a typo somewheres?
60x=24 x=2.5 ?? don't you think it is x= 24/60 = 2/5
See http://www.wolframalpha.com/input/?i=det+%7B+%7B0%2C7%2C9%7D%2C%7B0.4%2C1%2C2%7D%2C%7B0%2C9%2C3%7D%7D x= 0.4 so there must be a typo somewheres?
The book's solution would be correct if the first line of the matrix were 0 7 2 (rather than 0 7 9)