Adding and subtracting the given polynomials

You have to combine like terms, so the variable (x, y, s, d, c) and the exponents must be the same in order to combine them.

For example:

x² + x³    Since they don't have the same exponent, you can't combine them

y² + 3y² = 4y²

23x + x = 24x

4. 2s² + 1 + s² - 2s + 1    You can rearrange it if it makes it easier

2s² + s² - 2s + 1 + 1 = 3s² - 2s + 2

5. 5t² - 2t - 1 - (3t² - 5t + 7) Distribute/multiply the - to (3t² - 5t + 7)

5t² - 2t - 1 - 3t² + 5t - 7 = 2t² + 3t - 8

Do the same for #9 and #10, and you should get:

9. 2k² + 5k - 9

10. 6y³ - 7y² - 6y - 12

$4034.40

the perimeter of the field is the sum of the lengths of the four sides:

47 yd + 158 yd + 47 yd + 158 yd = 410 yd

the cost of 3 ft (1 yd) of fence is 3×$3.28 = $9.84.

so the cost of jake's wood perimeter fance is

(410 yd) × ($9.84 /yd) = $4034.40