Answer:
1.
[tex]x { }^{2} - 1[/tex]
2.
[tex]y {}^{2} + 8y + 15[/tex]
7.
[tex]m {}^{2} - 15m - 250[/tex]
13.
[tex]s {}^{2} - \frac{9}{16} [/tex]
21.
[tex]25m {}^{8} - 100[/tex]
28.
[tex]100p {}^{2} - 30pq + 390p - 117q[/tex]
37.
[tex]25a {}^{2} + 90ab + 81b {}^{2} [/tex]
