Question

c) x²+x/5=0........ e) 2x² + 5x =0........ f) -x² + 4x =0

Answer 1

c) x²+x/5=0

x² + x    = 0
      -----
        5

5x² + x  =  0
----------   -----
     5           5      

x.(5x + 1) = 0
x = 0

5x + 1 = 0
5x = - 1
x = - 1/5

R.: x = 0 e x = - 1/5

******************************
e)
2x² + 5x =0
x(2x + 5) = 0
x = 0

2x + 5 = 0
2x = - 5
x = - 5/2

R.: x = 0 e x = - 5/2

*********************************
f)
- x² + 4x =0

x( - x + 4) = 0
x = 0

- x + 4 = 0
- x = - 4 (-1)
x = 4

R.: x = 0 e x = 4