Find the ninth term of the geometric sequence, given the
first term and common ratio.
a =1 and r=-1/3

you need a common difference between consecutive terms to be constant, like 1,2,3,4 or 2,4,6,8, or 1,3,6,9

thats not a system of equations, that is a solution

y=-2.5x+12.5

step-by-step explanation:

5y=2x+10

y=0.4x+2

slope=-2.5

5=-2.5*3+b

b=12.5