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# p4 help PLEASE watch

1. using substitution ; y = v- x

find the general solution to

(x + y)dy/dx = x² + xy + x + 1
2. (Original post by mathematician)
using substitution ; y = v- x

find the general solution to

(x + y)dy/dx = x² + xy + x + 1
is v a function of x?
3. by the substitution,
v(dv/dx - 1) = x^2 + xv - x^2 + x +1
dv/dx = 1 + x + x/v + 1/v
dv/dx = 1 + x + (x+1)/v
dv/dx = (1+x)(1+1/v)
INT v/(v+1) dv = INT (1+x) dx
4. (Original post by keisiuho)
by the substitution,
v(dv/dx - 1) = x^2 + xv - x^2 + x +1
dv/dx = 1 + x + x/v + 1/v
dv/dx = 1 + x + (x+1)/v
dv/dx = (1+x)(1+1/v)
INT v/(v+1) dv = INT (1+x) dx
thanks... that working helped me ... i hate these types of questions (substitutions)... they don't often come up do they?

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