Question #b0e8c

1 Answer
Aug 1, 2015

You must solve this system of equations by substitution.

Explanation:

This problem looks really bad when you look at it. However, many times in mathematics, things that look bad really are not when you use basic principles.

Here we have a system of equations where the variables are already solved, The Y, C, &, I. This means it is set up perfectly for substitution.

We are going to take the equation:
#Y = C + I#
and substitute the #C# for the #a+bY# and #I# for the #u+vY#

here is what that looks like:
#Y= (a+bY) + (u+vY)#

solve for Y by moving all the Y to one side:
#Y = a+bY+u+vY#
#Y-bY-vY = a+u#

factor out the Y and you get:
#Y(1-b-v)=a+u#

then divide by the #(1-b-v)#:
#Y=(a+u)/(1-b-v)#

this is the solution for the total value of the economy in terms of just the constants. It really wasn't that hard and that makes us happy!
:)