2025年5月美国A卷练习 · 第 19 题

The solutions to \( x^2+6x+6=0 \) are r and s, where \( r<s \). The solutions to \( x^2+10x+13=0 \) are t and u, where \( t<u \). The solutions to \( x^2+16x+c=0 \), where c is a constant, are \( r+u \) and \( s+t \). What is the value of c?