How do you solve 72x - 8y = 40 and y = 9x + 5 using substitution?
1 Answer
Jul 9, 2016
This pair of equations is inconsistent; there are no solutions.
Explanation:
To see that there are no solutions:
Given
[1]color(white)("XXX")72x-8y=40
[2]color(white)("XXX")y=9x+5
substituting(9x+5) (from [2]) fory in [1]
[3]color(white)("XXX")72x-8(9x+5)=40
[4]color(white)("XXX")-40=40 (which is clearly impossible)
