Question

1. x+2y=3

2x-y=-4

2. x+y=1

y=-x+1

Answer 1

1.  x = 3- 2y

    -y = -4 - 2x  ===>  -y = -4 - 2(3-2y)

                              -y = -4 - 6 +4y

                              -y - 4y = -4-6

                              -5y = -10  /: (-5)

                                 y = 2

 

x = 3 - 2 * 2

x = 3 - 4

x = -1

 

2. x = 1 - y  

   y = -x + 1          ==>  y = -(1-y) +1

                                  y = -1 + y +1

                                  y-y =0

                                     0 = 0

wiele rozwiązań