1.\:\:expand\:(x^{2}+1)(x^{2}-1)
2.\:\:expand\:(x^{2}+5)(x^{2}-5)
3.\:\:expand\:(u^{3}+2)(u^{3}-2)
4.\:\:expand\:(x^{3}+2)(x^{3}-2)
5.\:\:expand\:(a^{2}+3)(a^{2}-3)
6.\:\:expand\:(a^{2}+4)(a^{2}-4)
7.\:\:expand\:(a^{2}+1)(a^{2}-1)
8.\:\:expand\:(a^{3}+5)(a^{3}-5)
9.\:\:expand\:(x^{3}+1)(x^{3}-1)
10.\:\:expand\:(u^{3}+4)(u^{3}-4)
