Question

Алгебра помогите пожалуйста 3 и 6

Answer 1

Ответ:

№ 3 - (x , y) = (9 , 3)

№ 6 - (x , y)= (3 , -7)  

Объяснение:

№ 3

$\left \{ {{x+y=12} \atop {x=3y}} \right. \\3y+y=12\\y=3\\x=3*3\\x=9\\\left \{ {{9+3=12} \atop {9=3*3}} \right. \\\left \{ {{12=12} \atop {9=9}} \right. \\(x,y) = (9,3)$

№ 6 $\left \{ {{2(3x-y)-5=2x-3y} \atop {5-(x-2y)=4y+16}} \right. \\\left \{ {{x=-\frac{1}{4}+\frac{5}{4} } \atop {5-(x-2y)=4y+16}} \right. \\5-(-\frac{1}{4}y+\frac{5}{4}-2y)=4y+16\\y=-7\\x=-\frac{1}{4}*(-7)+\frac{5}{4}\\x=3\\\left \{ {{2(3*3-(-7))-5=2*3-3*(-7)} \atop {5-(3-2*(-7))=4*(-7)+16}} \right. \\\left \{ {{27=27} \atop {-12=-12}} \right.\\(x,y)=(3,-7)$