Answer:
See below
Step-by-step explanation:
1.
[tex]\sqrt{\frac{36x^{2}}{y^{7}}} \\= \sqrt{\frac{6^{2}x^{2}}{y^{6}y}} \\=\frac{6x}{y^{3}\sqrt{y} } \\=\frac{6x\sqrt{y}}{y^{4} } \\[/tex]
2.
[tex](1-3i)(2+5i)-(3-12i)\\=2+5i-6i-15i^{2}-3+12i\\=14+11i[/tex]
** i^2=-1, -15i^2 = 15
3.
[tex]c=\sqrt{a^{2}+b^{2}} \\c^{2}=a^{2}+b^{2}\\a^{2}=c^{2}-b^{2}\\a=\sqrt{c^{2}-b^{2}}[/tex]