Algebra, help needed
posted by Mary Ann on .
I need help I don't know how to solve this system
Solve the following system. Show all your work
3x2y+2z= 30
x+3y4z= 33
2x4y+3z= 42

what makes it especially difficult? You must have solved similar systems already.
2(1st)+(2nd) and 3(1st)2(3rd):
5x  y = 27
5x + 2y = 6
Now it gets easier:
3y = 21
y = 7
so,
x = 4
z = 2 
every time i try adding two equations that could make it simpler ex; by adding and crossing out variables. i just could never get it right and still have those three same variables thx for the help

Yeah, it takes a bit of practice. Look for LCMs to get rid of stuff. In this case, since 3*2=6, we had to take 3 times the 1st to get 6 and 2 times the 3rd to get 6.
Usually the errors come in watching the other coefficients. In the beginning, it helps to write everything down so details don't get lost. 
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