Question 979076
(x-7) and (x-1) don't have a common factor, so just multiply them together.
{{{1/(x-7)}}} becomes {{{(x-1)/((x-1)(x-7))}}}
{{{3/(x-1)}}} becomes {{{(3(x-7))/((x-1)(x-7))}}}
you multiplied 1/(x-7) by (x-1)/(x-1)
you multiplied 3/(x-1) by (x-7)/(x-7)
note that (x-1)/(x-1) is equal to 1, so the net effect is to multiply 1/(x-7) by 1 which keeps the value the same.
ditto for multiplying by (x-7)/(x-7).