C=x-b solve for x do this i really need

7x+8y=-18, 4x-9y=-3 solve the system of equations

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.

Can any one me with the answers to these questions asap?