to Find dy/dx in terms of x and y if 7 x y + 4 x + y = 12
i have got 7yy'+7y'+4+y'=0
is that correct and does it simplify to y'=-4/7y or 2y'=-4/7y or neither?

Question

to Find dy/dx in terms of x and y if 7 x y + 4 x + y = 12
i have got 7yy'+7y'+4+y'=0 
is that correct and does it simplify to y'=-4/7y or 2y'=-4/7y or neither?

anonymous · Answer

Because you use the product rule, the x should not disappear..

anonymous · Answer

so 7xy'+7y'+4+y'...?  can you combine terms with y'?

anonymous · Answer

Not quite, when you do the product rule, its derivative of the first times the second, plus the first times the derivative of the second....

anonymous · Answer

Look at your second term, the 7y'... You took the derivative of the x and got 1, which was correct, but then you took the derivative of y as well.

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