Question

tim x 

1x5 + 4x - 78 = 100

Answer 1

<=>5x+4x=100-78=22

<=>x.(5+4)=22

<=>x.9=22

<=>x=22/9

Answer 2

1 x 5  + 4x - 78 = 100

5 + 4x = 178

=>  4x = 173

=>    x = 43,25

Answer 3

1x5 + 4x - 78 = 100

1x5 + 4x = 100 + 78

1x5 + 4x = 178

( 105 + x0 ) + ( 40 + x ) = 178

( 105 + 40 ) + ( x0 + x ) = 178

      145     +      xx       = 178

                        xx       = 178 - 145

                        xx       = 33

                         x        = 3

    Vậy x = 3

Answer 4

1x5+4x-78=100

5+4x-78=100

5+4x=100+78

5+4x=178

4x=178-5

4x=173

  x=173:4

  x=43,25