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2. Polynomials
medium
$x+1$ એ .... બહુપદીનો અવયવ છે.
A
$x^{3}+x^{2}-x+1$
B
$x^{3}+x^{2}+x+1$
C
$x^{4}+x^{3}+x^{2}+1$
D
$x^{4}+3 x^{3}+3 x^{2}+x+1$
Solution
If $x+1$ is a factor of $p(x),$ then $p(-1)=0$
$(a)$ Let $p(x)=x^{3}+x^{2}-x+1$
$\therefore \quad p(-1)=(-1)^{3}+(-1)^{2}-(-1)+1$
$=-1+1+1+1=2 \neq 0$
So, $x+1$ is not a factor of $p(x)$
$(b)$ Let $p(x)=x^{3}+x^{2}+x+1$
$\therefore \quad p(-1)=(-1)^{3}+(-1)^{2}+(-1)+1$
$=-1+1-1+1=0$
$(c)$ Let $p(x)=x^{4}+x^{3}+x^{2}+1$
$\therefore \quad p(-1)=(-1)^{4}+(-1)^{3}+(-1)^{2}+(-1)+1$
$=1-1+1+1=2 \neq 0$
$(d)$ Let $p(x)=x^{4}+3 x^{3}+3 x^{2}+x+1$
$\therefore \quad p(-1)=(-1)^{4}+3(-1)^{3}+3(-1)^{2}+(-1)+1$
$=1-3+3-1+1=1 \neq 0$
Hence, $x+1$ is a factor of $x^{3}+x^{2}+x+1$
So, $(b)$ is the correct answer.
Standard 9
Mathematics