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View Full Version : Solve sysems, graph


mathhater67
Jun 2, 2008, 01:32 PM
Please Help me. I have 7 problems that I need major help with! If nyone can help me it would be GREATLY appreciated!

29. 3x-y+4z=15
x+2y+2z=9
5x-3y-2z=7 solve the system

34. x-1/5y-z=6
1/3x+1/5y-1/4z=3
3x+y+1/4z=13
Is this dependent or inconsistent? (x,y,z)

27. 7x+6y+7z=1
7x-6y+7z=-1
21x+6y-7z=5
Is this dependent or inconsistent? (x,y,z)

26. 15a+6b+c=2
15a+18b+3c=5
a-2c+c=3
Is this dependent or inconsistent (x,y,z)

25. x+y+z=9
2x+y-z=11
4x-4y+z=11
Is this dependent or inconsistent? (x,y,z)

16. Fot the graph of the inequality y>2x. Find the equation of the boundary line and determine if the shaded half plane is above or below the boundary. Enter your answer as an equation and a word above or below separated by a comma

28. The owner of a candy store mixed some peanuts worth $4.00 per pound, some cashews worth $12.00 per pound, and some Brazil nuts worth $12.00 per pound to get 110 pounds of a mixture that would sell for $8.00 per pound. She used 35 fewer pounds of cashews than peanuts. How many pounds of each did she use? (x,y,z)

galactus
Jun 2, 2008, 04:53 PM
28. The owner of a candy store mixed some peanuts worth $4.00 per pound, some cashews worth $12.00 per pound, and some Brazil nuts worth $12.00 per pound to get 110 pounds of a mixture that would sell for $8.00 per pound. She used 35 fewer pounds of cashews than peanuts. How many pounds of each did she use? (x,y,z)

You will have three equations in three unknowns.

c=cashews, p=peanuts, b=brazil nuts.

4p+12c+12b=8(110)<----------total cost

p+c+b=110<-------------Total pounds of nuts

c=p-35<-----------35 less pounds of cashews than peanuts.

There is the system to solve. You can use substitution or elimination.

Once I have them set up, I usually run them through my calculator.