(a)
[tex]\frac{2}{3}x^2+1=55[/tex]
[tex]\frac{2}{3}x^2=54[/tex]
[tex]\frac{2}{3}x^2=54*\frac{3}{2}=81[/tex]
[tex]\pm 9[/tex]
Answer: x=-9 or 9
(b)
[tex]-2y^3-5=49[/tex]
[tex]-2y^3=54[/tex]
[tex]y^3=54/(-2)=-27[/tex]
[tex]y=(-27)^(1/3)=-3[/tex]
Answer: y=-3 (only real root)
