PLEASE HELP!!!! I really don't know how to do this!
Accepted Solution
A:
Answer:difference = 4πx +20π214 square unitsStep-by-step explanation:Part A.Do what the problem statement tells you, making the necessary substitutions. Difference of areas = Circle B area - Circle A area difference = π(x+6)² - π(x+4)² . . . . . . substitute for r in the circle formulas = π(x² +12x +36) -π(x² +8x +16) . . . . . expand the squares = π((x² -x²) +(12x -8x) +(36 -16)) . . . . . combine like terms = π(4x +20) . . . . . . . . . . . . . . . . . . . . . this is the result of combining terms difference = 4πx +20π . . . . . . . . . . . "simplified" form__Part B.For x=12, the above expression for the difference of areas becomes ... difference = (3.14)(4·12 +20) = 3.14·68 ≈ 214 . . . . square units