Which of the following is a linear polynomial?

Write the degree of the polynomial $5+3x^4$

Write the degree of the following polynomial.

$7$

Write the degree of the polynomial $a{x}^7+b{x}^9$ ($a,b$ are constants)

Write the following polynomial in standard form.

If $4x^2+7x^4-x^3-x+9=a{x}^4+b{x}^3+c{x}^2+dx+9$, find $a+b+c+d$.

If the polynomial $p+2p^3+10p^2+5p^4-8$ can be written in standard form as $a{p}^4+b{p}^3+c{p}^2+dp-8$, then find $a+b+c+d$.

Write the following polynomial in coefficient form.

$\left(x^4+16\right)$

The polynomial $a{x}^4+b{x}^3+c{x}^2+dx+e$ can be written in the coefficient form as $\left(a,b,c,d,e\right)$. Similarly, write the following polynomial in the coefficient form:

$m^5+2m^2+3m+15$

If the index form of the polynomial using variable $x$ from its coefficient form, $\left(3,-2,7,18\right)$ is $a{x}^4+b{x}^3+cx+d$, find $a+b+c+d$.