# linear equation and system of equations

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4. Decide whether the pair of lines is parallel, perpendicular, or neither.

4x+5y=5

5x+4y=7

8. Solve for x. 8x-(5x+7)=14

10. Simplify. -3[87-(-55-35)]

14. Find the domain of the function. p(x) = x^2 -2x + 7

23. Solve using the substitution method.

6x+7y=3

x=21-8y

30. Soybean meal is 18% protein; cornmeal is 9% protein. How many pound of each should be mixed together in order to get 360-lb mixture that is 15% protein?

34. In 1991, the life expectancy of males in a certain country was 69.7 year. In 1996, it was 72.0 years. Let E represent the life expectancy in year t and let t represent the number of years since 1991. What is the life expectancy of males in 2004?

42. Solve the following system of equations.

x+8y=6 (1)

x=3-8y (2)

44. The function H described by H(x)=2.75x+71.48 can be used to predict the height, in centimeters, of a woman whose humerus (the bone from the elbow to the shoulder) is x cm long. Predict the height of the woman whose humerus is 39 cm long.

46. The equation y=-1777x+27153 can be used to predict the number y of gun deaths in the United States x years after 2000, that is, x=0 corresponds to 2000, x=2 corresponds to 2002, x=6 corresponds to 2006, and so on. Predict the number of gun deaths in 2006 and 2009. In what year will the number of gun deaths be 7606?

50. Find the slope, if it exists, of the line containing the pair of points. (6,2) and (10,-4)

54. Trains A and B are traveling in the same direction on parallel tracks. Train A traveling at 80 miles per hour and train B is traveling at 84 miles per hour. Train A passes a station at 9:25 A.M. If train B passes the same station at 9:55 A.M., at what time will train B catch up to train A

55. Solve. 6 > -3x + 5 or 9 <=-4x + 2

#### Solution Summary

The solution shows how to set up and solve the system of equations in great detail.