Question 192b5685

Advanced Math - Nonlinear equations in one variable and systems of equations in two variables

The solutions to $x^{2} + 6 x + 7 = 0$ are $r$ and $s$ , where $r < s$ . The solutions to $x^{2} + 8 x + 8 = 0$ are $t$ and $u$ , where $t < u$ . The solutions to $x^{2} + 14 x + c = 0$ , where $c$ is a constant, are $r + t$ and $s + u$ . What is the value of $c$ ?