Question 123858
If you make any change to one side of an equation
you must make the same change to the other side, also.
That's the only rule you need.
{{{h - 9 = 2h - 1 }}}
I want to get all terms containing {{{h}}} on one side,
so first I'll add {{{1}}} to both sides
{{{h - 9 + 1 = 2h - 1 + 1}}}
The {{{1 - 1}}} on the right side equals zero
{{{h - 9 + 1 = 2h}}}
Now I want to subtract {{{h}}} from both sides
{{{h - h - 9 + 1 = 2h - h}}}
Notice I have {{{h - h = 0}}} on the left side
{{{-9 + 1 = 2h - h}}}
On the right side, {{{2h - h = h}}}
{{{-9 + 1 = h}}}
One more step. {{{-9 + 1 = -8}}} I don't have to do anything
to the other side this time, because I didn't really change
anything, I just did the addition
{{{-8 = h}}} answer