Help please is equations with letters

If f(x)=x^3 and g(x)=2x+7 when g(x)=-5

Which term best describes the association between variables a and b? no association a negative linear association a positive linear association a nonlinear association a scatterplot with an x axis labeled, variable a from zero to ten in increments of two and the y axis labeled, variable b from zero to one hundred forty in increments of twenty with fifteen points in a positive trend.

Find the center and the radius of the circle with the equation: x^2-2x+y^2+4y+1=0?