Question

resolva as equações do 1 grau a) x+9=0 b) x-9=-9 c) -2x=-72

Answer 1

a) x + 9 = 0
     x = -9 

b) x - 9 = - 9 
    x = -9+9
     x = 0 

c) -2x = - 72
      x = -72/-2
        x = 36                        ok

Answer 2

a) x+9=0

x= 0 - 9

x= - 9

b) x-9=-9

x= - 9 + 9

x= 0

c) -2x=-72(-1)

2x = 72

x= 72/2

x= 36