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If (-2,7) is the highest point on the gr...

If `(-2,7)` is the highest point on the graph of` y =-2x^2-4ax +lambda`, then `lambda` equals

A

31

B

11

C

`-1`

D

`-1/3`

Text Solution

Verified by Experts

The correct Answer is:
C

We have `-((-4a)/(2(-2)))=-2`
`impliesa=2`
`:.y=-2x^(2)-8x+lamda`…..i
Since Eq. (i) passes through points `(-2,7)`
`:.7=-2(-2)^(2)-8(-2)+lamda`
`implies7=-8+16+lamda`
`:.lamda=-1`
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