Punctul a)
[tex] 2x^2 =72 \ \big| :2 \\ x^2 =36 \ \big| \sqrt{} \\ \sqrt{x^2} =\sqrt{36} \implies |x|=6 \\ \tt x=\pm 6 \\ \tt S=\{-6,6\} [/tex]
Punctul b)
[tex] 2x^2 =50 \ \big| :2 \\ x^2 =25 \ \big| \sqrt{} \\ \sqrt{x^2} =\sqrt{25} \implies |x|=5 \\ \tt x=\pm 5 \\ \tt S=\{-5,5\} [/tex]
Punctul c)
[tex] 3x^2 =27 \ \big| :3 \\ x^2 =9 \ \big| \sqrt{} \\ \sqrt{x^2} =\sqrt{9} \implies |x|=3 \\ \tt x=\pm 3 \\ \tt S=\{-3,3\} [/tex]
Punctul d)
[tex] 5x^2 =80 \ \big| :5 \\ x^2 =16 \ \big| \sqrt{} \\ \sqrt{x^2} =\sqrt{16} \implies |x|=4 \\ \tt x=\pm 4 \\ \tt S=\{-4,4\} [/tex]
Cand am scris semnul asta:
“[tex] \ \big| \sqrt{} [/tex] “ inseamna ca iei radacina patrata din ambele parti. Adica bagi ambele expresii sub radical.
