Question

фигурная скобка 4x+5y=1 5x+7y=7

Answer 1

(4x+5y=1/(*(-5))
+
(5x+7y=7/(*4)
=
-20x-25y=(-5)
+
20x+28y=28
=
3y=23
y=23/3
4x+5*23/3=1
4x=1-115/3
4x=-112/3
x=-112/3*4
x=-28/3

Y=7 2/3
X=(-9 1/3)