Let a = b = {(x, y) | x belong to R, y belong to R}, mapping f ∶ a → B maps elements (x, y) in a to elements (X-Y, 2x + y) in B, Then under the mapping f, the corresponding element of element (1,2) in a in B is ▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁

Let a = b = {(x, y) | x belong to R, y belong to R}, mapping f ∶ a → B maps elements (x, y) in a to elements (X-Y, 2x + y) in B, Then under the mapping f, the corresponding element of element (1,2) in a in B is ▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁

First answer (- 1,4) second answer (1, - 1)