Answer:

Step-by-step explanation:
Area = pi*r^2
Area = pi*9^2
Area = 
f(x) = 5x − 1 and g(x) = 2x^2 + 1
(f × g)(x) = (5x − 1)(2x^2 + 1)
(f × g)(x) = 10x^3 - 2x^2 + 5x - 1
Substitute x = - 3
(f × g)(-3) = 10(-3)^3 - 2(-3)^2 + 5(-3) - 1
(f × g)(-3) = 10(-27) - 2(9) -15 - 1
(f × g)(-3) =-270 - 18 - 16
(f × g)(-3) = -236
Answer
- 236
C=x+9, c+x=99, c=99-x
So we have two equations equal to c, c=x+9 and c=99-x, since c=c:
x+9=99-x
2x+9=99
2x=90
x=45, and since c=x+9, c=54
So Charlie weighs 54 kg and his brother weighs 45 kg.