Polynomials

In case of a polynomial in one variable, the highest power of the variable is called the degree of the polynomial.
In case of polynomials in more than one variable, the sum of the powers of the variables in each term is taken up and the highest sum so obtained is called the degree of the polynomial.
In case of a polynomial in one variable, the highest power of the variable is called the degree of the polynomial.
In case of polynomials in more than one variable, the sum of the powers of the variables in each term is taken up and the highest sum so obtained is called the degree of the polynomial.
Simplify : $$m^5 \div m^8$$
Write the degree of each of the following polynomials:
$$\left( i \right)\,\,5{x^3} + 4{x^2} + 7x$$
$$\left( {ii} \right)\,\,4 - {y^2}$$
$$\left( {iii} \right)\,\,5t - \sqrt 7 $$
$$\left( {iv} \right)\,\,3$$
Which out of the following are expression with numbers only?
(a) $$y+3$$
(b) $$(7 \times 20)-8z$$
(c) $$5(21-7)+7 \times 2$$
(d) $$5$$
(e) $$3x$$
(f) $$5-5n$$
(g) $$(7 \times 20)-(5 \times 10)-45+p$$