2functii de gradul 1 la matematica pls dau coroana

What is the 17th term in the arithmetic sequence in which a6 is 101 and a9 is 83

The party planning committee has to determine the number of tables needed for an upcoming event. if a square table can fit 8 people and a round table can fit 6 people, the equation 150 = 8x + 6y represents the number of each type of table needed for 150 people.

Cos^2x+cos^2(120°+x)+cos^2(120°-x)i need this asap. pls me