CUET PG 2025 — Mathematics PYQ
CUET PG | Mathematics | 2025If x=(2+3)81+(2+3)−81 and x3−3x+k=0, then the value of k is:
Choose the correct answer:
- A.
-4
(Correct Answer) - B.
4
- C.
3
- D.
23
-4
Explanation
Maana ki y=(2+3)31
x=y+y1
Dono taraf cube karne par:
x3=(y+y1)3
x3=y3+y31+3(y)(y1)(y+y1)
x3=y3+y31+3x
x3−3x=y3+y31
Ab y3 ki value rakhne par:
y3=((2+3)31)3=2+3
y31=2+31=2−3
Inhe equation mein rakhne par:
x3−3x=(2+3)+(2−3)
x3−3x=4
Di gayi equation hai:
x3−3x+k=0
4+k=0
k=−4
Final Answer:
k=−4
Explanation
Maana ki y=(2+3)31
x=y+y1
Dono taraf cube karne par:
x3=(y+y1)3
x3=y3+y31+3(y)(y1)(y+y1)
x3=y3+y31+3x
x3−3x=y3+y31
Ab y3 ki value rakhne par:
y3=((2+3)31)3=2+3
y31=2+31=2−3
Inhe equation mein rakhne par:
x3−3x=(2+3)+(2−3)
x3−3x=4
Di gayi equation hai:
x3−3x+k=0
4+k=0
k=−4
Final Answer:
k=−4

