The number of integral roots of the equation x4+√x4+20=22 is
A
0
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B
2
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C
4
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D
8
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Solution
The correct option is B2 x4+√x4+20=22⇒√x4+20=22−x4 Squaring on both sides, ⇒x4+20=(22−x4)2 Assuming x4=t ⇒t+20=(22−t)2⇒t2−45t+464=0⇒(t−29)(t−16)=0⇒t=16,29⇒x4=16,29⇒x=±2,±(29)1/4
Hence, there are 2 integral values of x satisfying the equation.