Answer:
[tex]1 - (7 - 4x) = 9 \\ 1 - 7 + 4x = 9 \\ - 6 + 4x = 9[/tex]
and 6 to either sides:
[tex]( - 6 + 4x) + 6 = 9 + 6 \\ 4x = 15[/tex]
divide all sides by 4:
[tex] \frac{4x}{4} = \frac{15}{4} \\ \\ { \underline{ \underline{x \: \: is \: \: \frac{15}{4} }}}[/tex]
