Answer:
x = 21
Step-by-step explanation:
Vertical angles are congruent, this
3x - 30 = 2x - 9 ( subtract 2x from both sides )
x - 30 = - 9 ( add 30 to both sides )
x = 21
The boundaries:
x = 0, y = 8; y = 0, √x³ = = 8, x = 4


= π ( 64 x - 16 * 2 *√x^5 + x^4 / 4 ) =
= π ( 320 - 1024/5 + 64 ) =
179.2 π