to write a fraction in its simplest form we have to divide both numerator and denominator by a factor common to both
so we have to find the highest common factor for both 36 and 63
the factors for both numbers are as follows
36 -- 1, 2, 3, 4, 6, 9, 12, 18 and 36
63 - 1, 7, 9 and 63
the highest factor common for both is 9
so we can divide the fraction by 9
[tex] \frac{36/9}{63/9} = \frac{4}{7} [/tex]
the simplest form is 4/7