Question

решить систему методом подстановки 5x-2y=14; 2x+y=10

Answer 1

Y = 10 - 2X 
5X - 2*( 10 - 2X ) = 14 
5X - 20 + 4X = 14 
9X = 34 
X = 34/9 = 3 ( 7/9 ) 
Y = 10 - 2 * 34/9 = 10 - 68/9 = 10 - 7 ( 5/9 ) = 9 ( 9/9 ) - 7 ( 5/9 ) = 2 ( 4/9 )