Bài 1:
a: Thay a=50 vào T=500a+45000, ta được:
\(T=500\cdot50+45000=25000+45000=70000\)
b: Đặt T=155325
=>500a+45000=155325
=>500a=110325
=>\(a=\dfrac{110325}{500}=220,65\simeq221\)
Bài 2:
6x+5y+2xy=2
=>6x+2xy+5y=2
=>2x(y+3)+5y+15=17
=>2x(y+3)+5(y+3)=17
=>(2x+5)(y+3)=17
=>\(\left(2x+5\right)\cdot\left(y+3\right)=1\cdot17=17\cdot1=\left(-1\right)\cdot\left(-17\right)=\left(-17\right)\cdot\left(-1\right)\)
=>\(\left(2x+5;y+3\right)\in\left\{\left(1;17\right);\left(17;1\right);\left(-1;-17\right);\left(-17;-1\right)\right\}\)
=>\(\left(x,y\right)\in\left\{\left(-2;14\right);\left(6;-2\right);\left(-3;-20\right);\left(-11;-4\right)\right\}\)
