[tex]Greatest\ common\ factor\ is\ the\ highest\ number\ by\ witch\ 45\ and\ 90\\and\ 75\ can\ be\ divided\\\\
45:3\\
15:3\\5:5\\\\
90:2\\
45:3\\15:3\\5:5\\\\75:3\\25:5\\5:5\\\\\\GCF=3*5=15\\\\Greatest\ common\ factor\ of\ 45\ and\ 90\ and\ 75\ is\ equal\ to\ 15.
[/tex]
