6.3 Homework Problems 1. A computer repair service charges \( \$ 50 \) for a diagnosis and \( \$ 35 \) per hour for repairs. Let \( x \) be the number of hours it takes to repair a computer and let \( y \) be the total cost. a. Write a linear equation to model this scenario. b. Sally took her computer in and it required 2.5 hours to fix it. How much was her total bill? c. George paid \( \$ 155 \) to have his computer repaired. How many hours did the service technician work on his computer?

\( (2 x-3 y+z)(x+4 y-2 z) \) a) \( 2 x^{2}+5 x y-6 x z-12 y^{2}+13 y z-2 z^{2} \) b) \( 2 x^{2}+5 x y-4 x z-12 y^{2}+11 y z-2 z^{2} \) c) \( 2 x^{2}+8 x y-4 x z-12 y^{2}+11 y z-2 z^{2} \) d) \( 2 x^{2}-x y-4 x z-12 y^{2}+11 y z-2 z^{2} \)

Question If using the method of completing the square to solve the quadratic equation \( x^{2}+3 x-17=0 \), which number would have to be added to "complete the square"? Answer Attempt 2 out of 2

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

* 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) \( 3 x^{2} y+3 x y^{2} z-y^{3}-7 x y z+3 z^{2}+3 z^{3} \)

5) \( 2 z \geqslant z-7 \)