A polynomial is written correctly when the exponents are listed in order from highest to lowest. The highest exponent then dictates the degree of the whole polynomial. The first choice above is written in standard form from highest degree to lowest. Doesn't matter that we might skip the x-squared term or any other x-term, as long as they're in order from highest to lowest. The degree on that first polynomial, the one you're after, is 4 because that's the highest exponent, and there are 4 terms there. Terms are "bunches" of numbers and variables stuck together by multiplication and separated by + or - signs.
F(d)=(d+1)(d-1+6)
f(d)=(d+1)(d+5)
f(2)=(2+1)(2+5)
f(2)=(3)(7)
f(2)=21
99 would be to more than 89 because 89+10= 99<span />
The answer is 9 because if you find the two side lengths and find the area of the square then divide it by 2 it equals 9
