[tex]a) \\x^2-36=0 /+36\\x^2=36\\x=6 \text{ v } x=-6\\\\b) \\9x^2=1 /:9\\x^2=\frac19\\x=\frac13 \text{ v } x=-\frac13\\\\c) \\7-x^2=0\\7=x^2\\x^2=7\\x=\sqrt7 \text{ v } x=-\sqrt7\\\\d) \\81x^2+16=0\\81x^2=-16 /:81\\x^2=-\frac{16}{81}\\\\\text{brak miejsc zerowych}[/tex]
