Tip:A–D to answerE for explanationV for videoS to reveal answer
Let the set C={(x,y)∣x2−2y=2023,x,y∈N}. Then, ∑(x,y)∈C(x+y) is equal to.............
- A.
40
- B.
45
- C.
46
(Correct Answer) - D.
48
Explanation
\begin{aligned}
x^2 - 2y &= 2023 \\
x^2 &= 2023 + 2y \\
\text{let } y &= 1 \\
\Rightarrow x^2 &= 2023 + 2 \\
&= 2025 \\
x &= 45 \\
\therefore x + y &= 46
\end{aligned}
Explanation
\begin{aligned}
x^2 - 2y &= 2023 \\
x^2 &= 2023 + 2y \\
\text{let } y &= 1 \\
\Rightarrow x^2 &= 2023 + 2 \\
&= 2025 \\
x &= 45 \\
\therefore x + y &= 46
\end{aligned}
