a)(x-√5)(x+√5) b)(√7-y)(√7+y) c)(2x-√11)(2x+√11) d)(x√2-y)(x√2+y) e)(y√5-x√7)(y√5+x√7) f)(x√2-√3/3)(x√2+√3/3) g)(a√3-y√2/3)(a√3+y√2/3) h)(x√7/2-√10)(x√7/2+√10)