Respuesta :
if it is a fraction like (3a-3b)/(3a+12b)
= [3(a-b)]/[3(a+4b)]
= (a-b)/(a+4b)
= [3(a-b)]/[3(a+4b)]
= (a-b)/(a+4b)
3a-3b/3a+12b
Factor 3a-3b by 3
3(a-b)
Factor 3a+12b
3(4a+b)
3(a-b)/3(4a+b)
Cross out 3 and 3 , divide by 3
= a-b/4a+b
Answer: a-b/4a+b