Evaluate the surface integral. s x ds, s is the part of the plane 6x + 3y + z = 6 that lies in the first octant.

Three times the difference of federico’s age, and 4, increased by 7, is greater than 37. what are possible values of federico’s age?

Seymour is twice as old as cassandra. if 16 is added to cassandra’s age and 16 is subtracted from seymour’s age, their ages become equal. what are their present ages? show !

Lines a and b are perpendicular. if the slope of line a is 3, what is the slope of line b?