Find a cofunction with the same value as cos(2π/7

Solve x+3y=6 and 4x-6y=6 by elimination . show work !

Graph the line that represents a proportional relationship between d and t with the property that an increase of 33 units in t corresponds to an increase of 44 units in d. what is the unit rate of change of dd with respect to t? (that is, a change of 11 unit in t will correspond to a change of how many units in d? )

(x-5)1/2+5=2 what is possible solution of this equation