Question

the product of two rational number is 4/9 if one of them is -7/10 then find other

Answer 1

let the number be x
according to the question

-7/10*x=4/9
-7x/10=4/9
-7x=4*10/9
-7x*9=4*10
-63x=40
x=-40/63


hope it helps you

Answer 2

Here its your answer
-7/10 *  x     =   4/9
      x            =   4 * 10 / 9 * -7
      x            =   40 / -63