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Given that x2+4x+k=(x+r)2+1, find the va...

Given that x2+4x+k=(x+r)2+1, find the value of k and r

A.

k = 5, r = -1

B.

k = 5, r = 2

C.

k = 2, r = -5

D.

k = -1, r = 5

Correct answer is B

x2+4x+k=(x+r)2+1

x2+4x+k=x2+2rx+r2+1

Comparing the LHS and RHS equations, we have

2r=4r=2

k=r2+1=22+1=5