Chapter 1 - Introduction to Algebraic Expressions - 1.6 Subtraction of Real Numbers - 1.6 Exercise Set - Page 51: 149

The answer is below.

To do this problem, you need to use the negative sign, the minus sign (note that these two are not the same), and the parenthesis button. After all, parenthesis are necessary to to indicate the correct order of operations. (Of course, you also need to hit the $9$ and $7$ buttons.