Question

How do you solve the system `x − 2y = 14` and `x + 3y = 9` by substitution?

Answer 1

Replace one of the variables in one of the expressions with its value from the other expression and then solve.

x - 2y = 14 means that x = 14 + 2y
x + 3y = 9 means that (14 +2y) + 3y = 9
5y = 9 - 14 = -5
y = -1
x = 14 +2y = 14 - 2 = 12