Question

explain how to make equation please. i don't know how to make equation just make equation and solve them. answer blue marked

Answer 1

let the two digit's number be 10A+B,

then according to the question,we have

A+B=9,..............eq(1),

also

10A+B-9=4(10B+A),

10A+B-9=40B+4A,

then

10A-4A+B-40B=9,

6A-36B=9,

2A-12B=3,.................eq(2),

now solve these two equations.....