Multiply the bracket(s) to get rid of the brackets as this in the first step in BIDMAS/BODMAS.
#color(orange)(-7.3 xx x=-7.3x#
#color(blue)(-7.3 xx 7.1=-51.83#
This gives us #color(blue)(-100.47)=color(orange)(-7.3x)color(blue)(-51.83)color(orange)(-7.9x)#
Collect like terms on each side if possible, in this instance only the right...
#color(orange)(-7.3x + -7.9x=-15.2x#
This therefore leaves us with:
=> #color(blue)(-100.47)=color(orange)(-15.2x)color(blue)(-51.83)#
We want #x# on its own so therefore we do the opposite of #color(blue)(-51.83# which is adding #color(blue)(51.83# to both sides, as you have to add to both sides of the equation...
#color(blue)(-100.47)=color(orange)(-15.2x)color(blue)(-51.83)#
=> #color(blue)(-48.64)=color(orange)(-15.2x) color(Blue)((+51.83)#
Therefore to solve for #x#, we divide the total over how many #x's# we have which goes to...
#color(red)(x=-48.64/15.2#
As #-1 xx -1=1#
#color(red)(x=48.64/15.2=3.2#
Round if necessary, But in this case it's not, so leave it as:
=> #color(red)(x=3.2)#