If ordered pair (a + 2b, 9) = (7, 3a + 2b), then the values of a and b are
1, 3
Two ordered pairs are equal, if and only if the corresponding first elements are equal and the second elements are also equal.
Hence, a + 2b = 7 and 3a + 2b = 9.
Solving the linear equations, we get
a = 1 and b = 3