4 replies to this topic

[quangtohe]

a,x²+2y²+3xy+3x+5y=15

b,2x²+6y²+7xy-x-y=25

c,9x²-10y²-9xy+3x-5y=9

d,3^x-y³=1

e,1+x+x²+x³=2^y

[thanhmylam]

e) $(1+x)(x^{2}+1)=2^{y}$ nên 1+x=$2^{a}$, $x^{2}+1=2^{b}$ $\Rightarrow x^{2}+1 \vdots x+1$ . Vì x,y nguyên dương nên dễ dàng tìm được x,y  

Edited by thanhmylam, 03-02-2016 - 20:04.

[thanhmylam]

   d) $3^{x}=(y+1)(y^{2}-y+1)$ làm tương tự như phần e, ta tìm được x,y

[Coppy dera]

a,x²+2y²+3xy+3x+5y=15

b,2x²+6y²+7xy-x-y=25

c,9x²-10y²-9xy+3x-5y=9

d,3^x-y³=1

e,1+x+x²+x³=2^y

$a, (x+2y+1)(x+y+2)=17$

[Coppy dera]

a,x²+2y²+3xy+3x+5y=15

b,2x²+6y²+7xy-x-y=25

c,9x²-10y²-9xy+3x-5y=9

d,3^x-y³=1

e,1+x+x²+x³=2^y

$b,(3x-5y)(3x+2y+1)=9$

Edited by Coppy dera, 04-02-2016 - 13:04.