15 . A
Solve the equation for x. Squaring both sides, . So x = 7(2.74^2 ). Using
the calculator, x ≈ 52.55.
16 . E
For any point (u,v), , where r is the distance from (u,v) to the origin. See the
drawing below.
In this question, the distance r from point (a,b) to the origin is . So
.
17 . C
Use your calculator here.
18 . A
Try to solve the equation 30 x−5y^12 z−8 = 10 x−6y^5 z^4 for x in terms of y and z. Dividing both sides
by x−6, you have