Page 207 - How To Solve Word Problems In Calculus

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We integrate to get the area.
2

2
A = (8 − x − 2x) dx
−4
3 2
x
= 8x − − x 2
3
−4

8 64
= 16 − − 4 − −32 + − 16
3 3

28 80
= − −
3 3
108
=
3
= 36

2.

1 1 2 2 3 3

There appear to be three x intercepts. We first compute their
exact locations.

y = 0

3
2
x − 4x + 3x = 0
2
x(x − 4x + 3) = 0
x(x − 1)(x − 3) = 0

x = 0 x = 1 x = 3

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