What bout these oness?

Question

21 over 25= x over 75

andddddd.. 5 over 18 = 15 over a

help?

Answer 1

21/25 = x/75

multiply both numerator and denominator by 3,

63/75 = x/75

therefore, by comparison, x = 63

5/18 = 15/a

multiply both numerator and denominator by 3,

15/54 = 15/a

therefore, by comparison, a = 54

the cross multiplying method is better however i hope this helps you understand it better ;)

Answer 2

Cross multiply and solve for the variable: 25x = 21*75, 5a = 18*15