Mathematics puzzle

123456
Across
  1. 4. the number that are not rational number
  2. 5. y is the ________ variable
  3. 6. a number that can be expressed as a ratio of two integers is ____number
Down
  1. 1. The unknown in a linear equation
  2. 2. Result of a multiplication
  3. 3. equation of the form a x + b =0 called a_____equation