Question 1
SEAMO self-study edition 2027; not an official 2027 paper. Original source years are retained. 25 questions, 90 minutes; Q1–10: 3 points, Q11–20: 4 points, Q21–25: 6 points, total 100. Original response types and all subparts are preserved. Verified is an editorial convention; source defects, necessary assumptions and unresolved mathematical uncertainty are disclosed.
Given that $abcd$ is nonzero, $c,d$ are roots of $x^2+ax+b=0$, and $a,b$ are roots of $x^2+cx+d=0$, which expression equals $(a+b+c+d)^2$?
Given that $abcd$ is nonzero, $c,d$ are roots of $x^2+ax+b=0$, and $a,b$ are roots of $x^2+cx+d=0$, which expression equals $(a+b+c+d)^2$?