- Fill in the blanks to make each statement true. 1. We say that in the equation y = 3x +6, y is expressed in of x. 2. In the equation 3(x - 7) = 3x - 21, the was used to remove the parentheses. 3. A linear system with dependent equations has solutions. 4. In mathematics, to means to replace an expression with one that is equivalent to it. 5. The equation 2x + y = 8 expressed in y form is​