Enter the degree of the polynomial 5x5 + 8x2 + 2x – 3x9 – 8x4 – 4x5

The degree of a polynomial is the highest degree of any term.
The degree of a term is the sum of the exponents of all the variables of the term,. A plain variable has degree 1.
One term is -3x^9.
That has the largest exponent of any term, so the degree is 9.

-2x + 7 = 7

subtract 7 from both sides.

-2x = 0

divide both sides by -2.

x = 0

the value of x is equal to 0.