Find x in
a.) x:17 = 14:21
b.)7:3=21:x
please give fast tomorrow is my exam before 4 pm

a ) x : 17 = 14 : 21

= x / 17 = 14 /21

By cross multiplication we get

21 x = 17 * 14

= 21 x = 238

x = 238 / 21 = 11.33333333....

b ) 7 : 3 = 21 : x

= 7/3 = 21 / x

By cross multiplication we get

= 7x = 21 * 3

7x = 63 

= x = 63 / 7 = 9