I need help on number 17 please and number 18

asked Jan 15, 2021 163k views

1 vote

7.7k points

Please log in or register to add a comment.

5 votes

Answer:

17)

$16\pi(x^2+4x+4)$

18)

$A=\pi (6x+51)$

Explanation:

17)

$S=4 \pi r ^2\\r = (2x+4)\\r^2=(2x+4)^2 = 4x^2+16x+16\\S=16 \pi (x^2+4x+4)$

18)

$A=\pi r ^ 2\\A_(new)=A_(metal)-A_(hole)\\A=\pi((x+10)^2-(x+7)^2)\\A=\pi ((x^2+20x+100) - (x^2 + 14x + 49))\\A =\pi (6x+51)$

8.3k points

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers