MCQ
If $a + b + c = 9$ and $ab + bc + ca = 23$, then $a^2+b^2+c^2=$
- A$127$
- ✓$35$
- C$58$
- DNone of these.
✓
Answer
Correct option: B.
$35$
$(a+b+c)^2=a^2+b^2+c^2+2 a b+2 b c+2 c a$Hence, $9^2=a^2+b^2+c^2+2 \times 23$
$\Rightarrow a^2+b^2+c^2=35$
$\Rightarrow a^2+b^2+c^2=35$
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