What is 21/3= to in radical form

Iwant to know what 3g+5h+4g-2h is my teacher is too selfish to tell us

Which is a true statement comparing the graphs of x^2/6^2-y^2/8^2 = 1 and x^2/8^2-y^2/6^2 the foci of both graphs are the same points. the lengths of both transverse axes are the same. the directrices of = 1 are horizontal while the directrices of = 1 are vertical. the vertices of = 1 are on the y-axis while the vertices of = 1 are on the x-axis.

What is the point slope form of a line with slope -5 that contains point (2,-1)