What is the distributive property to create an equivalent expression to 9x +21

When only separate discreet points are graphed it is called?

7. if the value of x varies directly with the value of y, and x = 3 when y = 21. what is the valu y, and x = 3 when y = 21. what is the value of x when y = 105?

Identify the initial amount a and the growth factor b in the exponential function. a(x)=680*4.3^x