Add the total purchase then subtract the used amount from it. U'll get 2 1/3.
X = (15 - 8y)/9
-5[(15 - 8y)/9] + 12y = -107
(-75/9) + (40/9) + 12y = -107
y = -8.59
x = [15 - 8(-8.59)]/9
x = 9.3
(x,y) = (9.3, -8.59)
800,000 is the right answer.
For the function y = 7x - 1, if you state that the domain(or all the numbers you can substitute in for "x") of that function is the set of all real numbers, then you can assume that there will be an infinite number of solutions for the function.
In other words, if you substitute any real number in for "x" you will find that you will get a corresponding value for "y". In fact, these "pairs" of corresponding values of x and y are called ordered pairs and represent the various solutions of the equation.
Your response should be choice D: