100-((8•x-20•11):5+21)•7=175
100-
[tex]( \frac{8x - 220}{5} + 21) \times 7 = 175[/tex]
[tex]100 - \frac{7(8x - 220}{5} + 147) = 175[/tex]
[tex]100( \frac{56x - 1540}{5} + 147) = 175[/tex]
[tex]100 - \frac{56x - 1540}{5} - 147 = 175[/tex]
[tex] - 47 - \frac{56x - 1540}{5} = 175[/tex]
[tex] - 235 - (56x - 1540) = 875[/tex]
[tex] - 235 - 56x + 1540 = 875[/tex]
[tex]1305 - 56x = 875[/tex]
[tex] - 56x = 875 - 1305[/tex]
[tex] - 56x = - 430[/tex]
[tex]x \frac{215}{28} [/tex]
