Question 7 ( 4 points) The force exerted by the wind on a plane surface varies jointly with the square of the velocity of the wind and with the area of the plane surface. If the area of the surface is 39 square feet surface and the wind velocity is 15 miles per hour, the resulting force is 16 pounds. Find the force on a surface of 69 square feet with a velocity of 33 miles per hour. (round off your answer to 2 decimal places) Your Answer: Answer

Question If using the method of completing the square to solve the quadratic equation \( x^{2}+20 x+28=0 \), which number would have to be added to "complete the square"?

* 1 punto (2x \( \left.x^{2} y-3 x y z+z^{3}\right)-\left(x^{2} y-4 x y z-2 z^{3}\right)+\left(3 x y^{2} z-y^{3}+z^{2}\right) \) a) \( x^{2} y+x y^{2} z-7 x y z-y^{3}+3 z^{2}+3 z^{3} \) b) \( x^{2} y+3 x y^{2} z+y^{3}-7 x y z+3 z^{2}+z^{3} \) c) \( x^{2} y+3 x y^{2} z-y^{3}+x y z+3 z^{2}+3 z^{3} \) d) \( 3 x^{2} y+3 x y^{2} z-y^{3}-7 x y z+3 z^{2}+3 z^{3} \)

\( \left(2 x^{2} y-3 z\right)\left(x^{3} z+4 y^{2}\right) \) a) \( 2 x^{5} y z+8 x^{2} y^{3}-3 x^{3} z^{2}-12 z y^{2} \) b) \( 2 x^{5} y z+8 x^{2} y^{3}-3 x^{3} z^{2}-12 z^{2} y \) c) \( 2 x^{5} y z-8 x^{2} y^{3}+3 x^{3} z^{2}-12 z^{2} y \) d) \( 2 x^{5} y z+8 x^{2} y^{3}-3 x^{3} z^{2}-12 x^{2} z \)

2. La forma binómica del valor de \( z \) que satisface \( \frac{z}{i}+\frac{3 z-3 i}{1-i}=2-4 i \), es:

D. If \( f(x)=x^{2}-\pi \), what is \( f(-3) \) ? A. 6 B. -6 C. -12 D. 12