Question

1. Which of the following expressions is a difference UI
two squares? Factorise them.
(i) x2 - 49
(ii) x2 + 10
(iii) 4x2 - 16
(iv) - x2 - 64
(v) -14 9m²
(vi) -9 +49y2
(vii) 1644 - 49
(viii) x2 + 49
(ix) -144 - 9y2
(x) 144 + 81y2
(xi) -81 + 144y2
(xii) -36 - 4x2​