The function f is defined by f(x) is x^4 – 4x^2 + x + 1 for -5 ≤ x ≤ 5…

Here are a couple questions from the old official SAT Subject Test Math I practice exam:

The function f is defined by f(x) is x^4 – 4x^2 + x + 1 for -5 ≤ x ≤ 5. In which of the following intervals does the minimum value of f occur?
A) -5 ≤ x ≤ -3
B) -3 ≤ x ≤ -1
C) -1 ≤ x ≤ 1
D) 1 ≤ x ≤ 3
E) 3 ≤ x ≤ 5

Can you solve w/o graphing?

A video store rents, on average, 240 videos a day for $2.00 each…

A video store rents, on average, 240 videos a day for $2.00 each. The store determined that for every $0.25 that it increases the rental fee, the number of daily rentals will decrease by 10. This relationship can be represented by
y=(240-10n)(2+0.25n)
where y is the daily income in dollars from video rentals and n is the number of $0.25 increases. Based on this relationship, at what rental fee per video will the store have its highest daily income?
A)$2
B)$4
C)$4.25
D)$7.75
E)$8
SAT2 question:)

A tetrahedron was cut from the corner of a cube, with three of its vertices at the midpoints of three edges of the cube…

The following question comes from the subject test:
A tetrahedron was cut from the corner of a cube, with three of its vertices at the midpoints of three edges of the cube. If tetrahedrons of the same size are cut from the remaining seven corners of the cube, how many faces will the resulting solid have?

Thank you and big hugs!