How can i solve and check the following fraction?

Question

4/x = 5/7

Answer 1

crossmultiply

that is to say - multiply both sides by x ... then multiply both sides by 7

you should get 28 = 5x

then solve for x

You check your solution by putting the value you get for x back into the first equation LHS and see if it comes out equalling the RHS.

Answer 2

4/x = 5/7
4 *7/5 = x
x = 28/5

u can check by substituting x = 28/5 in 4/x = 5/7
4 / (28/5) =5/7
4* 5/28 =5/7
5/7 =5/7
LHS=RHS
Hence proved.

Answer 3

4 / x = 5 / 7
28 = 5x
x = 28 / 5