Nth term of this quadratic sequence 9,18,31,48,69

Use the four functions below for this question. compare and contrast these four functions using complete sentences focus on the slope and y- intercept first, and then on any additional properties of each function

What happens to the area as the sliders are adjusted? what do you think the formula for the area of a triangle is divided by 2?

Which expressions equal 9 when x=4 and y=1/3 a. x2+6y b. 2x + 3y c. y2-21x d. 5 (x/2) -3y e. 3x-9y